The rifle's average bullet velocity. Bullet speed from pneumatics. The effect of barrel length
Live cartridge for small arms consists of a bullet, a powder charge, a sleeve and a primer (Scheme 107).
Scheme 107. Live cartridge
Sleeve designed to connect together all the elements of the cartridge, to prevent the breakthrough of powder gases when fired (obturation) and to preserve the charge.
The sleeve has a muzzle, slope, body and bottom (see diagram 107). In the bottom of the sleeve there is a capsule socket with a septum, anvil and seed holes (Scheme 108). The anvil protrudes into the capsule socket, which is made from the outer surface of the bottom of the sleeve. The percussion composition of the capsule is broken on the anvil with a striking force to ignite it, through the seed holes the flame from the capsule penetrates to the powder charge.
Capsule designed to ignite the powder charge and is a cup-cap, at the bottom of which a shock compound is pressed, covered with a foil circle (see diagram 107). To ignite gunpowder, so-called initiating substances are used, which are highly sensitive and explode from mechanical stress.
The cap used for assembling the elements of the capsule is inserted into the capsule socket with some interference in order to eliminate the breakthrough of gases between its walls and the walls of the capsule socket. The bottom of the cap is made strong enough so that it does not break through with the striker's striker and does not break through from the pressure of the powder gases. The capsule cap is made of brass.
The impact composition ensures trouble-free ignition of the powder charge. For the preparation of the shock composition, explosive mercury, potassium chlorate and antimony are used.
Mercury fulminate Hg (ONC) 2 is an initiator in the impact composition. Advantages of explosive mercury: preservation of its qualities during long-term storage, reliability of action, ease of ignition and comparative safety. Disadvantages: intensive interaction with the metal of the barrel, which increases the corrosion of the barrel, amalgamation (coating with mercury) of the primer cap, which leads to its spontaneous cracking and the breakthrough of powder gases. To eliminate the latter drawback, the inner surface of the cap is varnished.
Potassium chlorate KClO 3 is an oxidizing agent in the shock composition, ensures complete combustion of the components, increases the combustion temperature of the shock composition and facilitates the ignition of the powder. It is a colorless crystalline powder.
Antimony Sb 2 S 3 is combustible in the striking composition. It is a black powder.
The impact composition of the primer of a rifle cartridge contains: explosive mercury 16%, potassium chlorate 55.5% and antimony 28.5%.
The foil circle protects the primer composition from destruction during shocks of cartridges (during transportation, feeding) and from moisture ingress. The foil circle is varnished with shellac-rosin varnish.
The capsule is pressed into the capsule sockets in such a way that the foil covering the capsule composition falls without stress on the anvil (Scheme 109).
Scheme 108. Scheme of a capsule socket with a primer:
1 - anvil
Scheme 109. Capsule:
1 - cap; 2 - shock composition; 3 - foil circle
The burning speed of smokeless powder and the quality of the shot depend to a large extent on the quality of the primer's actuation. The capsule must form a flame of a certain length, temperature and duration of action. These qualities are united by the term "force of the flame". But primers, even of very good quality, may not give the necessary flame force if the striker strikes poorly. For a full-fledged flash, the impact energy must be 0.14 kg m. This is the energy that the shock mechanisms of modern sniper rifles have. But the shape and size of the striker are also important for the full-fledged ignition of the capsule's warhead. With a normal striker and a strong mainspring of the cleaned percussion mechanism, the force of the capsule flame is constant and ensures stable ignition of the powder charge. With a rusty, dirty, worn-out trigger mechanism, the impact energy on the primer will be different, with dirt, the output of the striker for impact will be small, therefore, the flame force will be different (Scheme 110), the combustion of the gunpowder will be uneven, the pressure in the barrel will change from shot to shot ( more - less - more), and do not be surprised if an unclean weapon suddenly gives noticeable "breaks" up and down.
Scheme 110. Forced flame of the same capsules in different conditions:
A - striker correct shape and values at the required impact energy;
B - very sharp and thin striker;
B - firing pin of normal shape with low impact energy
Powder charge is intended for the formation of gases, ejecting a bullet from the bore. The source of energy when firing is the so-called propelling powder, which have an explosive transformation with a relatively slow increase in pressure, which makes it possible to use them for throwing bullets and projectiles. V modern practice rifled barrels, only smokeless propellants are used, which are divided into pyroxylin and nitroglycerin propellants.
Pyroxylin powder is made by dissolving a mixture (in certain proportions) of wet pyroxylin in an alcohol ether solvent.
Nitroglycerin powder is made from a mixture (in certain proportions) of pyroxylin with nitroglycerin.
The following are added to smokeless propellants: a stabilizer - to protect the propellant from decomposition, a phlegmatizer - to slow down the burning rate and graphite - to achieve flowability and eliminate adhesion of powder grains.
Pyroxylin powder is used mainly in ammunition for small arms, nitroglycerin, as more powerful, in artillery systems and grenade launchers.
When the powder grain burns, its area decreases all the time, and accordingly the pressure inside the barrel decreases. In order to equalize the working pressure of gases and provide a more or less constant combustion area of the grain, the powder grains are made with internal cavities, namely, in the form of a hollow tube or ring. The grains of such gunpowder burn simultaneously from the inner and outer surfaces. The decrease in the external combustion surface is compensated for by the increase in the internal combustion surface, so that the total area remains constant.
FIRE PROCESS IN THE BARREL
The powder charge of a rifle cartridge weighing 3.25 g burns out in about 0.0012 s when fired. When the charge burns, about 3 calories of heat are released and about 3 liters of gases are formed, the temperature of which at the time of the shot is 2400-2900 ° C. The gases, being highly heated, exert high pressure (up to 2900 kg / cm 2) and eject a bullet from the barrel at a speed of over 800 m / s. The total volume of red-hot powder gases from the combustion of a powder charge of a rifle cartridge is about 1200 times larger in volume than the powder before the shot was fired.
A shot from small arms occurs in the following order, from the impact of the striker on the primer of a live cartridge locked in the chamber, its initiating substance, sandwiched between the sting of the striker and the anvil of the sleeve, ignites, this flame is thrown through the seed holes to the powder charge and covers the powder grains. The entire charge of gunpowder ignites almost simultaneously. A large amount of gases formed during the combustion of gunpowder creates high pressure on the bottom of the bullet and the walls of the case. This gas pressure creates an extension in the width of the walls of the sleeve (while maintaining their elastic deformation), and the sleeve is tightly pressed against the walls of the chamber, preventing, like an obturator, the breakthrough of the powder gases back to the bolt.
As a result of the pressure of gases on the bottom of the bullet, it moves from its place and cuts into the rifling. Rotating along the rifling, the bullet moves along the bore with a continuously increasing speed and is ejected along the axis of the bore.
The pressure of gases on the opposite walls of the barrel and chamber also causes their slight elastic deformation and is mutually balanced. The pressure of the gases on the bottom of the cartridge case of the cartridge locked by the bolt causes the weapon to move backward. This phenomenon is called giving. According to the laws of mechanics, recoil increases with an increase in the powder charge, bullet weight and with a decrease in the weapon's own weight.
All countries try to make ammunition of very high quality. Despite this, from time to time there is a manufacturing defect or ammunition deteriorates from improper storage. Sometimes, after hitting the primer with a striker, the shot will not follow or it happens with some delay. In the first case, there is a misfire, in the second, a prolonged shot. The cause of a misfire is most often the dampness of the percussion composition of the primer or powder charge, as well as a weak impact of the striker on the primer. Therefore, it is necessary to protect the ammunition from moisture and keep the weapon in good condition.
The protracted shot is a consequence of the slow development of the propellant charge ignition process. Therefore, after a misfire, do not immediately open the shutter. Usually, after a misfire, five to six seconds are counted and only after that the shutter is opened.
When a powder charge is burned, only 25-30% of the released energy is spent as useful work to eject a bullet. For minor work - cutting into grooves and overcoming the friction of a bullet when moving along the bore, heating the walls of the barrel, sleeve and bullet, moving moving parts in an automatic weapon, ejecting a gaseous and unburned part of the powder - up to 20% of the energy of the powder charge is used. About 40% of the energy is not used and is lost after the bullet leaves the bore.
The task of the powder charge and the barrel is to accelerate the bullet to the required flight speed and give it destructive combat energy. This process has its own characteristics and takes place in several periods.
The preliminary period lasts from the beginning of the combustion of the powder charge to the complete penetration of the shell of the bullet into the rifling of the barrel. During this period, gas pressure is created in the barrel bore, which is necessary to move the bullet from its place and overcome the resistance of its shell to cutting into the rifling of the barrel. This pressure is called the boost pressure, it reaches 250-500 kg / cm 2 depending on the geometry of the rifling, the weight of the bullet and the hardness of its shell. The combustion of the powder charge in this period occurs in a constant volume, the shell cuts into the rifling instantly, and the movement of the bullet along the barrel begins immediately when the boost pressure is reached in the barrel bore. The gunpowder still continues to burn at this time.
The first, or main, period lasts from the beginning of the movement of the bullet until the moment of complete combustion of the powder charge. During this period, the combustion of the powder occurs in a rapidly changing volume. At the beginning of the period, when the speed of movement of the bullet along the bore is not yet high, the amount of gases grows faster than the volume of space between the bottom of the bullet and the bottom of the sleeve (bullet space), the gas pressure rises rapidly and reaches its maximum value - 2800-3000 kg / cm 2 (see Schemes 111, 112). This pressure is called maximum pressure. It is created in small arms when a bullet travels 4-6 cm. Then, due to the rapid increase in the speed of the bullet, the volume of the bullet space increases faster than the influx of new gases, the pressure in the barrel begins to drop, and by the end of the period it reaches about 3/4 of the desired initial bullet speed. The powder charge burns out shortly before the bullet leaves the bore.
Scheme 111. Change in gas pressure and increase in bullet velocity in the barrel of a rifle sample 1891-1930.
Scheme 112. Change in gas pressure and bullet velocity in the barrel of a small-bore rifle
The second period lasts from the moment of complete combustion of the powder charge until the moment the bullet leaves the bore. With the beginning of this period, the flow of powder gases stops, however, the highly compressed and heated gases continue to expand and, continuing to exert pressure on the bullet, increase the speed of its movement. The pressure drop in the second period occurs rather quickly and at the muzzle is 570-600 kg / cm 2 for a rifle.
The third period, or the period of gas aftereffect, lasts from the moment the bullet leaves the bore until the moment the powder gases stop acting on the bullet. During this period, the propellant gases flowing out of the bore at a speed of 1200-2000 m / s continue to act on the bullet and impart additional velocity to it. The bullet reaches its highest, maximum speed at the end of the third period at a distance of several tens of centimeters from the muzzle of the barrel. This period ends at the moment when the pressure of the propellant gases at the bottom of the bullet is balanced by the air resistance.
What are the practical implications of all of the above? Take a look at graph 111 for a 7.62mm rifle. Based on the data of this graph, it becomes clear why the length of the rifle barrel practically does not make sense to make more than 65 cm.If you make it longer, the bullet speed increases very slightly, and the dimensions of the weapon senselessly increase. It becomes clear why a three-line carbine with a barrel length of 47 cm and a bullet speed of 820 m / s has practically the same fighting qualities, as well as a three-line rifle with a barrel length of 67 cm and an initial bullet speed of 865 m / s.
A similar picture is observed for small-bore rifles (diagram 112) and especially for weapons chambered for a 7.62-mm automatic cartridge of the 1943 model.
The length of the rifled barrel of the AKM assault rifle is only 37 cm with an initial bullet speed of 715 m / s. The length of the rifled part of the barrel of the Kalashnikov light machine gun, firing the same cartridges, is 54 cm, 17 cm longer, and the bullet accelerates slightly - the muzzle velocity of the bullet is 745 m / s. But in rifles and machine guns, the barrel has to be made elongated for greater accuracy of the battle and to lengthen the aiming line. These parameters provide increased firing accuracy.
INITIAL BULLET SPEED
The initial velocity is one of critical characteristics combat properties of weapons. With an increase in the initial speed, the range of the bullet, the range of a direct shot, the lethal and penetrating action of the bullet increase, and the influence external conditions on her flight. In particular, the faster the bullet flies, the less it is blown away by the wind. The value of the initial velocity of the bullet must be indicated in the firing tables and in the combat characteristics of the weapon.
The magnitude of the initial velocity of the bullet depends on the length of the barrel, the weight of the bullet, the weight, temperature and moisture content of the powder charge, the shape and size of the powder grains, and the loading density.
The longer the barrel, the longer the propellant gases act on the bullet and the greater (within the known technical limits, see earlier) the initial velocity.
With a constant barrel length and constant weight of the powder charge, the lower the bullet weight, the higher the initial velocity.
A change in the weight of the powder charge leads to a change in the amount of powder gases, and, consequently, to a change in the value of the maximum pressure in the bore and the initial velocity of the bullet. The more gunpowder, the more pressure and the more the bullet accelerates along the barrel.
The length of the barrel and the weight of the powder charge are balanced according to the above graphs (schemes 111, 112) of internal fire processes in the rifle barrel when designing and assembling weapons to the most rational dimensions.
With the rise outside temperature the combustion rate of the propellant increases, and therefore the maximum pressure and initial velocity increase. As the outside temperature drops, the initial speed decreases. In addition, as the outside temperature changes, the barrel temperature also changes, and more or less heat is needed to heat it up. And this, in turn, affects the change in pressure in the barrel and, accordingly, the initial velocity of the bullet.
One of the old snipers in the memory of the author in a specially sewn bandolier carried a dozen rifle cartridges under his arm. When asked what it mattered, the elderly instructor replied, "Very great importance... You and I were both shooting at 300 meters, but your scatter went up and down vertically, while mine did not. Because the gunpowder in my cartridges warmed up to 36 degrees under the arm, and yours in the pouch froze to minus 15 (it was in winter). You shot a rifle in the fall at plus 15, a total difference of 30 degrees. You shoot with frequent fire, and your barrel is hot, so your first bullets went lower, and the second - higher. And all the time I shoot gunpowder of the same temperature, so everything flies as expected. "
An increase (decrease) in the initial speed causes an increase (decrease) in the firing range. The differences in these values are so significant that in the practice of hunting shooting from smoothbore guns, summer and winter barrels of different lengths are used (winter barrels are usually 7-8 cm longer than summer ones) to achieve the same shooting range. In sniper practice, range corrections for air temperature must be made according to the corresponding tables (see earlier).
With an increase in the moisture content of the powder charge, its combustion rate decreases and, accordingly, the pressure in the barrel and the initial velocity drop.
The combustion rate of the powder is directly proportional to the surrounding pressure. In the open air, the burning rate of a smokeless rifle powder is approximately 1 m / s, and in confined space chamber and barrel due to pressure increase, the rate of combustion of the powder increases and reaches several tens of meters per second.
The ratio of the weight of the charge to the volume of the sleeve with the bullet inserted (the combustion chamber of the charge) is called the loading density. The more the gunpowder is "rammed" in the sleeve, which occurs with an overdose of gunpowder or a deep landing of the bullet, the more the pressure and combustion rate increase. This sometimes leads to a sharp jump in pressure and even to the detonation of the powder charge, which can lead to rupture of the barrel. The loading density is made according to complex engineering calculations and for a domestic rifle cartridge is 0.813 kg / dm3. With a decrease in the loading density, the burning rate decreases, the time for the bullet to travel along the barrel increases, which, paradoxically, leads to a rapid overheating of the weapon. For all these reasons, reloading live ammunition is prohibited!
SPECIFIC FEATURES OF LOW-CALIBRATION (5.6 MM) SIDE FIRE CARTRIDGES
The capsule charge in the side fire cartridges is pressed from the inside into the rim of the sleeve (the so-called Flaubert cartridge), and the striker for the shot is struck, respectively, not in the center, but along the edge of the bottom of the sleeve. In small-caliber cartridges with a solid lead shellless bullet, the powder charge is very insignificant and with a low loading density (the powder is poured up to half the case volume). The pressure of the powder gases is insignificant and emits a bullet with an initial velocity of 290-330 m / s. This is because more pressure can rip the soft lead bullet off the rifling. For sports purposes and biathlon, the above bullet speed is sufficient. But at a low external air temperature with even a slight lack of powder, the pressure in the small-bore barrel can drop sharply, when the pressure drops, the gunpowder stops burning and there are often cases when at minus 20 ° C and below the bullets simply get stuck inside the barrel. Therefore, in winter at subzero temperatures, it is recommended to use cartridges of increased power "Extra" or "Biathlon".
Bullet theory
The bullet is a destructive element. The range of its flight depends on the specific gravity of the material from which it is made.
In addition, this material must be malleable to cut into the rifling of the barrel. This material is lead, which has been used to make bullets for several centuries. But a soft lead bullet with an increase in the powder charge and pressure in the barrel breaks off the rifling. The muzzle velocity of the solid lead bullet of the Berdan rifle did not exceed 420-430 m / s, and this was the limit for a lead bullet. Therefore, the lead bullet began to be enclosed in a shell of a more durable material, or rather, molten lead was poured into this strong shell. Such bullets used to be called two-layer bullets. With a two-layer device, the bullet retained as much weight as possible and had a relatively strong shell.
The shell of the bullet, made of a material that was more durable than the lead that filled it, did not allow the bullet to break off the rifling under strong pressures inside the barrel and allowed to dramatically increase the initial velocity of the bullet. Moreover, with a strong shell, the bullet was less deformed when it hit the target and this improved its penetrating (piercing) action.
Bullets, consisting of a dense shell and a soft core (lead filling), appeared in the 70s of the XIX century following the invention of smokeless powder, which provides an increased working pressure in the barrel. It was a breakthrough in development firearms, which made it possible in 1884 to create the world's first and very successful famous machine gun"Maksim". The shell bullet provided increased survivability of rifled barrels. The fact is that soft lead "enveloped" the barrel walls, hammered the rifling, which sooner or later caused the barrel to swell. In order to prevent this from happening, lead bullets were wrapped in salted thick paper, and still it did not help much. In modern small-caliber weapons firing lead shellless bullets, in order to avoid enveloping the lead, the bullets are coated with a special technical fat.
The material from which the bullet shell is made must be plastic enough so that the bullet can cut into the grooves, and strong enough so that the bullet does not fall off when moving along the grooves. In addition, the bullet jacket material should have the lowest possible coefficient of friction in order to wear out the barrel walls less and be resistant to rusting.
Cupronickel meets all these requirements - an alloy of 78.5-80% copper and 21.5-20% nickel. Bullets with cupronickel shell have proven themselves in service better than any others. But cupronickel was very expensive in the mass production of ammunition.
Bullets with a cupronickel shell were produced in pre-revolutionary Russia. During the First World War, in the absence of nickel, bullet shells were forced to be made of brass. In the civil war, both the red and the white made ammunition from whatever they had to. The author has seen cartridges of those years with bullet shells made of brass, thick copper and mild steel.
In the Soviet Union, bullets with cupronickel shells were produced until 1930. In 1930, instead of cupronickel, for the manufacture of shells, they began to use low-carbon mild steel clad (coated) with tombak. Thus, the bullet shell became bimetallic.
Tompak is an alloy of 89-91% copper and 9-11% zinc. Its thickness in the bimetallic shell of the bullet is 4-6% of the shell wall thickness. The bimetallic shell of a bullet with a tombak coating basically met the requirements, although it was somewhat inferior to the shells of cupronickel.
Due to the fact that the production of tombak coatings requires scarce non-ferrous metals, before the war in the USSR they mastered the production of casings from cold-rolled low-carbon steels. These shells were covered with a thin layer of copper or brass by an electrolytic or contact method.
The core material in modern bullets has sufficient high fever melting. For this, an alloy of lead and antimony is used in the ratio of 98-99% lead and 1-2% antimony. Antimony impurity makes the lead core somewhat stronger and increases its melting point.
The above-described bullet, which has a sheath and a lead core (fill), is called ordinary. Among ordinary bullets, there are solid bullets, for example, a French solid tombak bullet (Scheme 113), a French elongated solid aluminum bullet (4 in Scheme 114), as well as lightweight bullets with a steel core. The appearance of a steel core in ordinary bullets is caused by the requirement to reduce the cost of the bullet design by reducing the amount of lead and reducing the deformation of the bullet in order to increase the penetrating action. Between the bullet sheath and the steel core is a lead jacket to facilitate cutting into the grooves.
Scheme 113 French solid tompak bullet
Scheme 114. Ordinary bullets:
1 - domestic light, 2 - German light; 3 - domestic heavy; 4 - French solid; 5 - domestic with a steel core; 6 - German with a steel core; 7 - English; 8 - Japanese A - annular groove - knurling for attaching the bullet in the sleeve
Old-fashioned bullets are still in use. There are light bullets of the 1908 model with a cupronickel shell without annular knurling for fixing the bullet in the sleeve (Scheme 115) and a light bullet of the 1908-1930 model. with a steel sheath clad with a tompak, having a circular knurling for better fixing of the bullet in the muzzle of the cartridge case when assembling the cartridge (A in diagram 114).
Scheme 115. Light bullet sample 1908 without knurling
The materials from which the bullet shell is made wear out the barrel in different ways. The main cause of barrel wear is mechanical abrasion, and therefore the harder the bullet shell, the more intense the wear. Practice has shown that when firing from the same type of weapon with bullets with different casings, made at different times at different factories, the survivability of the barrel is different. When firing a bullet with a wartime steel shell not clad with a tombak, barrel wear sharply increases. The uncoated steel shell tends to rust, which drastically reduces shooting accuracy. Such bullets were fired by the Germans in last months World War II.
In the design of the bullet, the head, leading and tail parts are distinguished (Scheme 116).
Scheme 116.Functional parts of a 1930 sample bullet:
A - head, B - leading, B - tail streamlined
The head part of a modern rifle bullet has an elongated conical shape. The higher the speed of the bullet, the
its head should be longer. This situation is dictated by the laws of aerodynamics. The elongated conical nose of the bullet has less aerodynamic drag when flying in the air. For example, an ogival blunt-pointed bullet of a three-line rifle of the first model of production before 1908 gave a 42% decrease in speed on the way from 25 to 225 m, and a pointed bullet of 1908 on the same path - only 18%. In modern bullets, the length of the bullet head is selected in the range from 2.5 to 3.5 caliber weapons. The leading part of the bullet cuts into the rifling.
The purpose of the leading part is to give the bullet a reliable direction and rotational movement, as well as to tightly fill the grooves of the rifling of the barrel in order to eliminate the possibility of a breakthrough of powder gases. For this reason, bullets in thickness are made with a larger diameter than the nominal caliber of the weapon (Table 38).
Table 38
Data of 7.62 mm rifle cartridges produced in the USSR at different times
As a rule, the leading part of the bullet is cylindrical, sometimes a slight taper is given for the smooth penetration of the leading part of the bullet. For a better direction of movement of the bullet along the bore and to reduce the likelihood of stalling from the rifling, it is more advantageous to have a large length of the leading part, moreover, with its greater length, the accuracy of the battle increases. But with an increase in the length of the leading part of the bullet, the effort required to cut the bullet into the rifling increases. This can lead to lateral rupture of the shell. With regard to barrel survivability, protection of the shell from bursting and ensuring better air flow in flight, a shorter leading part is more advantageous.
The long leading part wears out the barrel more intensively than the short one. When firing an old Russian blunt-pointed bullet with a larger leading part, the survivability of the barrels was half that when firing a new pointed bullet of the 1908 model with a shorter leading part. In modern practice, the limits of the length of the leading part are from 1 to 1.5 of the size of the caliber.
From the point of view of shooting accuracy, the length of the leading part is unprofitable to take less than one bore diameter along the groove grooves. Bullets that are shorter than the rifling diameter of the bore give more spread.
In addition, a decrease in the length of the leading part leads to the possibility of its breakdown from the rifling, to incorrect flight of the bullet in the air and deterioration of its obturation. With a small length of the leading part of the bullet, gaps are formed between the bullet and the bottom of the groove groove. Red-hot powder gases with solid particles of unburned gunpowder rush into these gaps at high speed, which literally "lick" the metal and dramatically increase barrel wear. A bullet that goes along the barrel not tightly, but "walking" along the rifling, gradually "breaks" the barrel and worsens the quality of its further work.
The rational ratio between the length of the leading part of the bullet and the diameter of the barrel bore along the groove grooves is also selected depending on the material of the bullet shell. Bullets with a softer shell material than steel can have a leading part length slightly greater than the rifling diameter of the barrel. This value can be no more than 0.02 groove caliber.
The fastening of the bullet in the sleeve is carried out by rolling or crimping the muzzle of the sleeve into the circular knurling of the bullet, which is usually done closer to the front end of the leading part. The muzzle of knurled steel sleeves will not "remove chips" and deform the chamber when a cartridge is fed into it.
A lot depends on the fastening of the bullet in the sleeve. With a weak fastening, forcing pressure does not develop; with a very dense powder, it burns out in a constant volume of the sleeve, which causes a sharp jump in the maximum pressure in the barrel, up to rupture. When firing cartridges with different bullet rolling, there will always be a spread of bullets in height.
The tail of the bullet can be flat (like a light bullet of the 1908 model) or streamlined (like a heavy bullet of the 1930 model) (see diagram 116).
BALLISTIC BULLETS
At supersonic speeds, where the main cause of air resistance is the formation of an air seal in front of the warhead, bullets with an elongated pointed nose are beneficial. A rarefied space is formed behind the bottom part of the bullet, as a result of which a pressure difference appears on the head and bottom parts. This difference determines the air resistance to the flight of the bullet. The larger the diameter of the bullet bottom, the larger the rarefied space, and, naturally, the smaller the bottom diameter, the smaller this space is. Therefore, the bullets are given a streamlined tapered shank, and the bottom of the bullet is left as small as possible, but sufficient to fill it with lead.
It is known from external ballistics that at a bullet speed greater than the speed of sound, the shape of the bullet tail has a comparatively less effect on air resistance than the bullet head. With a high initial bullet velocity at firing distances of 400-450 m, the general aerodynamic picture of air resistance for bullets with both a flat and a streamlined tail section is approximately the same (A, B in diagram 117).
Scheme 117. Ballistics of bullets of different shapes at different speeds:
A - ballistics of a bullet with a tapered shank at high speeds;
B - ballistics of a bullet without a tapered shank at high and low speeds;
B - ballistics of a bullet with a tapered shank at low speeds:
1 - a wave of compacted air; 2 - separation of the boundary layer; 3 - sparse space
The influence of the shape of the tail section on the magnitude of the air drag force increases with decreasing bullet velocity. The tail section in the form of a truncated cone gives the bullet a more streamlined shape, due to which, at low speeds, the area of rarefied space and air turbulence behind the bottom of the flying bullet are reduced (B in diagram 117). Turbulence and the presence of an area of reduced pressure behind the bullet result in a rapid loss of bullet velocity.
A tapered tail section is more appropriate for heavy bullets used for firing at long distances, since at the end of a long-range flight, the bullet speed is low. In modern bullets, the length of the tail conical part is in the range of 0.5-1 caliber.
The total length of the bullet is limited by the conditions of its stability during flight. With a normal steepness of the grooves, the stability of the bullet in flight is ensured when its length is no more than 5.5 caliber. A bullet of a longer length will fly at the stability limit and even with natural eddies of air currents it can go somersault.
LIGHT AND HEAVY BULLETS. BULLET TRANSVERSE LOAD
The transverse load of a bullet is the ratio of the weight of the bullet to the cross-sectional area of its cylindrical part.
a n = q / S n (g / cm 2),
where q is the weight of the bullet in grams;
S n is the cross-sectional area of the bullet in cm 2.
The greater the weight of a bullet with the same caliber, the greater its lateral load. Depending on the magnitude of the lateral load, a distinction is made between light and heavy bullets. Ordinary bullets with a normal caliber (see below) having a lateral load of more than 25 g / cm 2 and a weight of more than 10 g are called heavy, and bullets of a normal caliber having a weight of less than 10 g and a lateral load of less than 22 g / cm 2 are called lungs (Table 39).
Table 39
Basic data of the 1908 light bullet and the 1930 heavy bullet
Bullets with a high lateral load have a lower muzzle velocity than light bullets at the same maximum barrel pressure. Therefore, at short firing ranges, a light bullet gives a more flat trajectory than a heavy bullet (Scheme 118). However, as the lateral load increases, the acceleration of the air drag force decreases. And since the acceleration of the air resistance force acts in the direction opposite to the bullet speed, bullets with a higher lateral load slowly lose speed under the influence of air resistance. For example, a domestic heavy bullet at a distance of more than 400 m has a more flat trajectory than a light bullet (see diagram 118).
Scheme 118. Trajectories of light and heavy bullets when firing at different ranges
Of no small importance is the fact that a heavy bullet has a tapered shank and its aerodynamics at low speeds is more perfect than the aerodynamics of a light bullet (see earlier).
For all these reasons, upon reaching a distance of 500 m, a light bullet of the 1908 model begins to slow down, but a heavy one does not (Table 40).
Table 40
Bullet flight time, s
It has been established by practice that heavy bullets at distances of 400 m provide more accurate combat and are stronger on the target than light bullets. Of rifles and machine guns, the maximum flight range of a heavy bullet is 5000 m, and a light bullet is 3800.
For conventional infantry rifles, of which the shooting by poorly trained shooters, as a rule, is carried out at distances of up to 400 m, shooting with light bullets will be practical, because at this distance the trajectory of a light bullet will be more flat, and therefore more effective. But for snipers and machine gunners who need to reach a target at 800 m (and machine gunners further), it is more expedient and effective to shoot with heavy bullets.
For a better understanding of the process, we will give a ballistic interpretation of scheme 118. In order for a heavy bullet to hit the same point as a light bullet when firing at a distance of 200 m, it must be given a greater elevation angle when firing, that is, to "raise" the trajectory by almost one or two centimeters ...
If the rifle is shot with light bullets at a distance of 200 m, heavy bullets at the end of the distance will go one and a half to two centimeters lower (if the sight is installed for shooting light bullets). But at a distance of 400 m, the speed of a light bullet already falls faster than the speed of a heavy bullet, which has a more perfect aerodynamic shape. Therefore, at a distance of 400-500 m, the trajectories and hit points of both bullets coincide. At longer ranges, a light bullet loses its speed even more than a heavy one. At a shooting distance of 600 m, a light bullet hits the same point as a heavy one if it is fired at a greater elevation angle. That is, now it is necessary to raise the trajectory already when firing a light bullet. Therefore, when firing from a rifle shot with heavy bullets, at a distance of 600 m, light bullets will go lower (actually by 5-7 cm). Heavy bullets at firing ranges over 400-500 m have a more flat trajectory and greater accuracy, so they are more preferable for firing at distant targets.
A light bullet sample of 1908 has a lateral load of 21.2 g / cm 2. heavy bullet sample 1930 - 25.9 g / cm 2 (Table 39).
The bullet weight of the 1930 sample is made due to an elongated nose and a tapered tail (b in diagram 119). Light bullet sample 1908-1930 has a conical recess in the tail section - The presence of this internal cone (and in diagram 119) creates favorable conditions for obturation of powder gases, since the tail section of the bullet expands in diameter due to gas pressure and is tightly pressed against the walls of the barrel bore.
Scheme 119. Light and heavy bullets:
a - light bullet; b - heavy bullet:
1 - sheath: 2 - core
This circumstance makes it possible to increase the service life of the barrel, because a light bullet cuts well into the rifling, presses against them and receives a rotational motion even with a very low rifling height. Thus, the inner hollow cone of a light bullet, with its lower mass and inertia, increases the survivability of the barrels.
For the same reason, shooting with a light bullet from old rifles with worn-out barrels is more accurate and effective than shooting with heavy bullets. A heavy bullet, when passing through the old barrel, is "combed" by the roughness of the shells from rust and heat, like a file, decreases in diameter and, when it leaves the barrel, begins to "walk" in it. The light bullet is constantly expanded to the sides by its tapered skirt and, while working in the barrel, is pressed against its inner walls.
Remember: shooting with a light bullet doubles the survivability of the barrels. From the new barrels, the firing quality (accuracy of combat) is better when firing a heavy bullet. From old, worn-out barrels, the firing quality is better when firing a light bullet with an inner taper of the tail section.
Light bullets have the advantage of a flat trajectory up to a range of 400-500 m. From a range of 400-500 m and more, a heavy bullet has advantages in all respects (bullet energy is higher, dispersion is less and the trajectory is flatter). Heavy bullets are less deflected by derivation and wind, as much less as they weigh more than a light bullet (about 1/4). At distances over 400 m, the probability of a hit when firing a heavy bullet is three times higher than when firing a light bullet.
When zeroing in at a distance of 100 m, heavy bullets go 1-2 cm lower than light bullets.
The nose (tip) of a 1930 heavy bullet turns yellow. The light bullet of the 1908 model has no special distinguishing marks.
ACTION OF THE BULLET ON THE TARGET. Bullet lethality
The defeat of a live open target when it hits it is determined by the lethality of the bullet. The lethality of a bullet is characterized by the live force of the impact, that is, the energy at the moment of meeting the target. Bullet energy E depends on the ballistic properties of the weapon and is calculated by the formula:
E = (g x v 2) / S
where g is the weight of the bullet;
v is the speed of the bullet at the target;
S is the acceleration of gravity.
The greater the weight of the bullet and the greater its initial velocity, the greater the energy of the bullet. Accordingly, the greater the bullet velocity at the target, the greater the bullet energy. The speed of the bullet at the target is the greater, the more perfect its ballistic qualities, determined by the shape of the bullet and its streamlining. To inflict a defeat that incapacitates a person, a bullet energy equal to 8 kg m is sufficient, and to inflict the same defeat on a pack animal, an energy of about 20 kg m is needed. Bullets of modern army models of small arms caliber 7.62 mm retain their lethality almost to the maximum distance flight. Bullets of sports small-bore cartridges very quickly lose speed and energy. In practice, such a small-caliber bullet loses its guaranteed lethality at a distance of more than 150 m (Table 41).
Table 41
Ballistic data of a 5.6 mm small-bore bullet
When firing at normal aiming distances, the bullets of all types of military small arms have a multiple reserve of energy. For example, when firing a heavy bullet from a sniper rifle at a distance of 2 km, the bullet energy at the target is 27 kg m.
The effect of a bullet on live targets depends not only on the energy of the bullet. Factors such as "lateral action", the bullet's ability to deform, and the speed and shape of the bullet are of great importance. "Lateral action" - a blow to the sides - is characterized not only by the size of the wound itself, but also by the size of the affected tissue adjacent to the wound. From this point of view, pointed long bullets have a large "lateral" effect due to the fact that a long bullet with a light head part begins to "tumble" when it hits living tissue. The so-called "tumbling" bullets with a displaced center of gravity were known at the end of the last century and were repeatedly prohibited by international conventions due to the monstrous effect: a bullet tumbling through the body leaves behind a channel about five centimeters in diameter, filled with crushed minced meat. In general military practice, the attitude towards them is ambiguous - these bullets, of course, kill on the spot, but in flight they go to the limit of stability and often begin to somersault even from strong gusts of wind. In addition, the penetrating action of somersaults on the target leaves much to be desired. For example, when firing such a bullet through a wooden door, a tumbling bullet makes a huge hole in the door, and this is where its energy is exhausted. The target behind this door has a chance to survive.
The bullet's ability to deform increases the target area. Shellless lead bullets, when they hit the tissue of a living organism, are deformed in the front part and cause very severe wounds. In hunting practice, for shooting at large animals from rifled weapons, the so-called expansive expanding semi-sheathed bullets are used. The leading part of these bullets and a little of the head part are enclosed in a shell, and the nose is left weakened, sometimes a lead fill "looks out" from the shirt, sometimes this fill is covered with a cap, sometimes a counter body is made in the head part (Scheme 120). These bullets sometimes burst into pieces when they meet a target and therefore were called explosive in the old days (this is a wrong name). The first samples of such bullets were made in the 70s of the XIX century in the Dum-Dum arsenal near Calcutta, and therefore the name Dum-Dum stuck to semi-shell bullets of various calibers. In military practice, such bullets with a soft nose are not used due to their small penetrating action.
Scheme 120. Unfolding bullets:
1 - firms "Rose"; 2 and 3 - firms "Western"
For the lethal effect of a bullet big influence has its speed. Man is 80% water. An ordinary pointed rifle bullet, when it hits a living organism, causes a so-called hydrodynamic shock, the pressure from which is transmitted in all directions, causing general shock and severe destruction around the bullet. However, the hydrodynamic effect is manifested when firing at live targets at a bullet speed of at least 700 m / s.
Along with the lethal effect, there is also the so-called "stopping effect" of a bullet. The stopping effect is the ability of a bullet, when it hits the most important organs, to quickly upset the functions of the enemy's body so that it cannot provide active resistance. With a normal stopping action, a living target should be instantly disarmed and immobilized. The stopping effect is of great importance at point-blank range and increases with an increase in the caliber of the weapon. Therefore, the calibers of pistols and revolvers are usually made larger than rifle calibers.
For sniper shooting, usually carried out at medium distances (up to 600 m), the stopping effect of a bullet of particular importance does not have.
SPECIAL ACTION BULLETS
When conducting hostilities, it is impossible to do without bullets of special action - armor-piercing, incendiary, tracer, etc.
Cartridges with armor-piercing bullets designed to defeat the enemy behind armored cover. Armor-piercing bullets differ from ordinary bullets by the presence of an armored core of high strength and hardness. Between the jacket and the core there is usually a soft lead jacket, which makes it easier for the bullet to penetrate the rifling and protects the bore from intense wear. Sometimes armor-piercing bullets do not have a special shirt. Then the shell, being the body of the bullet, is made of a soft material. This is how the French armor-piercing bullet (3 in diagram 121) is arranged, consisting of a tombak body and a steel armor-piercing core. The nose of the armor-piercing bullet is painted black.
Scheme 121. Armor-piercing bullets:
1- domestic; 2 - Spanish; 3 - French
The armor-piercing action of bullets is usually advantageous to combine with other types of action: incendiary and tracer. Therefore, the armor-piercing core is found in armor-piercing incendiary and armor-piercing incendiary-tracer bullets.
Tracer bullets are designed for target designation, fire correction when firing up to 1000 m.Such bullets are filled with a tracer compound, which for uniform combustion is pressed in several steps under very high pressure in order to avoid destruction of the composition when fired, burning it on a large surface and destroying the bullet in flight ( and in diagram 122). In the shell of domestically produced tracer bullets, a lead-antimony alloy core is placed in the front, and a glass with a tracer compound pressed into several layers at the back.
Scheme 122. Tracer bullets:
a - bullet T-30 (USSR); b - SPGA bullet (England); c - bullet T (France)
In order to avoid the destruction of the compressed tracer composition in the bullet and disruption of its normal combustion, the tracer bullets usually do not knurl (groove) on the side surface to crimp the neck of the sleeve into it. The fastening of tracer bullets in the muzzle of the case is provided, as a rule, by landing them in the muzzle with an interference fit.
When fired, the flame from the powder charge ignites the tracer composition of the bullet, which, burning in the flight of the bullet, gives a bright luminous trail, clearly visible both day and night. Depending on the time of manufacture and the use of various components in the manufacture of the tracer composition, the glow of the tracer can be green, yellow, orange and crimson.
The most practical is the crimson glow, which is clearly visible at night and during the day.
A feature of tracer bullets is the change in weight and movement of the center of gravity of the bullet as the tracer burns out. Weight change and longitudinal displacement of the center of gravity do not affect harmful influence on the nature of the bullet's flight. But the lateral displacement of the center of gravity caused by one-sided burnout of the tracer makes the bullet dynamically unbalanced and causes a significant increase in dispersion. In addition, during the combustion of the tracer, chemically aggressive combustion products are released, which have a destructive effect on the bore. It doesn't matter when firing a machine gun. But the sniper's perfect and accurate barrel must be protected. So don't overuse the tracer sniper rifle shooting. Moreover, the accuracy of firing tracer bullets from the best barrel leaves much to be desired. Moreover, a tracer bullet with a loss of weight from the combustion of the tracer quickly loses its penetrating ability and does not even penetrate a helmet at a distance of 200 m. The nose of the tracer bullet is colored green.
Incendiary bullets were fired before and during World War II. These bullets were intended to destroy flammable targets. In their designs, the incendiary composition was most often placed at the head of the bullet and worked (ignited) when the bullet hit the target (Scheme 123). Some incendiary bullets, for example French (and in the diagram 123), lit up even in the bore from powder gases. The author has seen the shooting of such bullets during forensic shooting. The sight was very impressive from the shooter across the range beautiful yellow-orange balls the size of a soccer ball went. But there was absolutely no combat effect from this fireworks. Incendiary bullets, which appeared at the end of the First World War to fight the enemy's plywood-linen airplanes, turned out to be untenable against all-metal aircraft. French, Polish, Japanese, Spanish incendiary bullets did not have the necessary penetrating ability and were not able to pierce and set fire to even a railway tank car. The situation was not saved even by the fact that subsequently the incendiary composition began to be placed inside a strong steel case. The nose of the incendiary bullet is colored red.
Scheme 123. Incendiary bullets:
a - French bullet Ph: 1 - shell, 2 - phosphorus, 3, 4 and 5 - bottom part, 6 - fusible plug; b - Spanish bullet P 1 - core, 2 - point, 3 - heavy body, 4 - incendiary composition (phosphorus); c - German bullet SPr 1 - shell, 2 - incendiary composition (phosphorus), 3 - bottom part; 4 - low-melting plug; d - English bullet SA: 1 - shell, 2 - incendiary composition, 3 - bottom part; 4 - low-melting plug
Due to their low penetration, incendiary bullets quickly began to be pushed out of combat use by armor-piercing incendiary bullets, which usually had a tungsten carbide or steel armor-piercing core. The combination of incendiary and armor-piercing action turned out to be very beneficial. Designs of armor-piercing incendiary bullets during World War II in different countries were different (Scheme 124). Usually, the incendiary composition was still located at the head of the bullet - this way it worked more reliably, but set it on fire worse. Not all of the igniting substance penetrated after the armor-piercing core into the hole it formed. To avoid this drawback, it is more advantageous to place the incendiary composition behind the armor-piercing core, but in this case, the sensitivity of the bullet ignition to action against weak obstacles is reduced. The Germans originally solved this problem, they placed the incendiary composition around the armor-piercing core (4 in diagram 124, diagram 125).
Scheme 124 Armor-piercing incendiary bullets:
1 - domestic, 2 - Italian; 3 - English; 4 - Germanic
Scheme 125. Armor-piercing incendiary bullet RTK caliber 7.92 (German)
The head of the armor-piercing incendiary bullets is painted black with a red belt.
Armor-piercing incendiary-tracer bullets have an armor-piercing, incendiary and tracer effect at the same time. They consist of the same elements: a shell, an armor-piercing core, a tracer, and an incendiary composition (Scheme 126). The presence of a tracer in these bullets significantly increases their incendiary effect. The nose of an armor-piercing incendiary-tracer bullet is colored purple and red.
Scheme 126. Armor-piercing incendiary-tracer bullets:
1 - domestic BZT-30;
2 - Italian
Before World War II, so-called sighting-incendiary bullets were used in the armies of some countries (in particular, the USSR and Germany). In theory, they were supposed to give a bright flash at the moment of meeting even with a plywood shield of an ordinary target. These bullets both in the USSR and in Germany had the same design. The principle of their operation was usually based on the fact that the striker, located on the axis of the bullet and intended for piercing the primer, in the stowed state was held in place by mutually closed counterbalance weights. These counterweights, when fired and the bullet rotated, diverged to the sides by centrifugal force, released or cocked the drummer. When meeting the target and braking the bullet, the drummer pricked the primer, which ignited the incendiary composition, giving a very bright flash. Once in DOSAAF, where they gave for training purposes any cartridge "rabble" unnecessary in the army, the author fired such cartridges of release 1919 (!). The cartridges were with a brass sleeve and a brass bullet sheath, gunpowder detonated from old age and the weapon hit hard in the shoulder. At a distance of 300 m, flashes from these bullets were visible on a bright sunny day with the naked eye. These bullets were essentially explosive, for they really burst into fragments when they hit the plywood shield. At the same time, a hole was formed into which you could stick your fist. According to eyewitnesses, hitting a living target with such bullets had dire consequences. This ammunition was banned by the Geneva Convention and was not produced during the Second World War, of course, not for the sake of humanism, but because of the high cost of production. Old stocks of cartridges with such bullets were used. For sniper shooting, such bullets are unsuitable due to the large (very large) dispersion. The nose of a sighting-incendiary bullet, like that of a conventional incendiary, turns red. These were the very famous explosive bullets that were not advertised either in our country or in Germany. Their device is shown in diagrams 127, 128.
Scheme 127. Explosive bullets:
a - remote bullet (Germany); b - shock bullet (Germany); c - shock bullet (Spain)
Scheme 128. Explosive inertial bullets:
1 - shell; 2 - explosive;
3 - capsule; 4 - fuse; 5 - drummer
The above-described varieties of special bullets are used in all cartridges of small arms, not excluding even pistol cartridges, if they are used for firing from submachine guns.
Domestic bullets are assigned the following designations: P - pistol; L - ordinary light rifle; PS - ordinary with a steel core; T-30, T-44, T-45, T-46 - tracer; B-32, BZ - armor-piercing incendiary; BZT - armor-piercing incendiary-tracer; PZ - sighting and incendiary; 3 - incendiary.
These markings can be used to identify the type of ammunition in the ammunition box.
At the present time, the most practical light ordinary bullets, tracer and armor-piercing incendiary, have remained in combat use.
In the warehouses of NZ, there are still quite large stocks of cartridges with all the types of bullets described above, and from time to time these cartridges are supplied both for practice shooting and for combat use. In galvanized form, combat rifle cartridges can be stored for 70-80 years without losing their fighting qualities.
Small-caliber gross sports and hunting cartridges produced in the USSR could be stored for 4-5 years without changing the fighting qualities. After this period, they began to change the accuracy of the battle in height due to the uneven combustion of gunpowder in different cartridges. After 7-8 years of storage in such cartridges due to the decomposition of the primer composition, the number of misfires increased sharply. After 10-12 years of storage, many lots of these cartridges became unusable.
Target small-caliber cartridges, made very high quality and scrupulously, stored in sealed packages and galvanized, did not lose their qualities with a shelf life of 20 years or more. But small-caliber cartridges should not be stored for a long time, because they are not designed for long storage periods.
Cartridges for firearms rifled weapons in all states of the world they try to do it as efficiently as possible. Classic mechanics cannot be fooled. For example, a slight change in the weight of a bullet from the calculated one does not have a significant effect on the accuracy of fire at short distances, but with an increase in the range it makes itself felt quite strongly. When the weight of an ordinary rifle light bullet changes by 1% (Vstart - 865 m / s), the deviation of the trajectory in height at a distance of 500 m will be 0.012 m, at 1200 m - 0.262 m, at 1500 m - 0.75 m.
In sniper practice, a lot depends on the quality of the bullet.
The height of the trajectory of a bullet is influenced not only by its weight, but also by the initial velocity of the bullet and the geometry of its streamlining. The initial velocity of the bullet, in turn, is influenced by the size of the powder charge and the material of the shell: different material provides different friction of the bullet against the barrel wall.
Balancing the bullet is essential. If the center of gravity does not coincide with the geometric axis, then the spread of bullets increases, therefore, the accuracy of shooting decreases. This is often observed when firing bullets with various mechanical non-uniform filling.
The less deviations in shape, weight and geometrical dimensions in the manufacture of a bullet of this design, the better the accuracy of shooting, other things. equal conditions.
In addition, it must be borne in mind that rust on the shell of the bullet, nicks, scratches and other deformations are very adversely reflected in the flight of the bullet in the air and lead to a deterioration in the accuracy of fire.
The maximum pressure of the propellant gases ejecting the bullet is influenced by the initial force pressure, which cuts the bullet into the rifling, which in turn depends on how tightly the bullet is pressed into the sleeve and fixed in it by crimping the muzzle for the knurled knurl. With different liner materials, this force will be different. A bullet that is slanted into the sleeve will go “obliquely” along the grooves; it will be unstable in flight and will definitely deviate from the given direction. Therefore, cartridges of old issues must be carefully inspected, selected and discarded if errors are found.
The best accuracy of fire is given by ordinary bullets, in which the shell is filled with lead without other filling. When shooting at a live target, special bullets are not needed.
As you have already seen, rifle ammunition that looks the same and intended for the same weapon is not the same. For several decades, they were made in different factories, from various materials, in different conditions, with constantly changing requirements of the situation, with bullets of different designs, different weight, different fillings with lead, different diameters (see table 38) and different quality of workmanship.
The same seemingly cartridges have a different bullet trajectory and different accuracy of the battle. When firing from a machine gun, it does not matter - plus or minus 20 cm higher or lower. But for sniper shooting, this is not suitable. The "rabble" of various cartridges, even the best ones, does not provide accurate, heap and monotonous shooting.
Therefore, the sniper selects exactly for his barrel (barrel to barrel is also different, see below) monotonous cartridges, one series, one plant, one year of production and, even better, from one box. Different batches of cartridges differ from each other in the height of the trajectory. Therefore, under different batches of cartridges, sniper weapons must be re-shot.
Bullet Penetration
The penetrating action of a bullet is characterized by the depth of its penetration into an obstacle of a certain density. Living force bullet at the moment of its meeting with an obstacle significantly affects the depth of penetration. But besides this, the penetrating effect of a bullet depends on a number of other factors, for example, on the caliber, weight, shape and design of the bullet, as well as on the properties of the penetrated medium and on the angle of encounter. The meeting angle is the angle between the tangent to the trajectory at the meeting point and the tangent to the surface of the target (obstacle) at the same point. The best result is obtained at a meeting angle of 90 °. Diagram 129 shows the meeting angle for the case of a vertical obstacle.
Scheme 129. Meeting angle
To identify the penetrating action of a bullet, they use the measurement of its penetration into a package made up of dry pine boards 2.5 cm thick each, with gaps between them by the thickness of the board. When firing at such a package, a light bullet from a sniper rifle penetrates: from a distance of 100 m - up to 36 boards, from a distance of 500 m - up to 18 boards, from a distance of 1000 m - up to 8 boards, from a distance of 2000 m - up to 3 boards
The penetrating action of a bullet depends not only on the properties of the weapon and the bullet, but also on the properties of the penetrated barrier. A light rifle bullet, model 1908, penetrates at a distance of up to 2000 m:
Iron plate 12 mm,
Steel plate up to 6 mm,
A layer of gravel or crushed stone up to 12 cm,
Sand or earth layer up to 70 cm,
A layer of soft clay up to 80 cm,
Peat layer up to 2.80 m,
Packed snow layer up to 3.5 m,
Straw layer up to 4 m,
Brick wall up to 15-20 cm,
Oak wood wall up to 70 cm,
Pine wood wall up to 85 cm.
Bullet penetration depends on the firing distance and the angle of impact. For example, an armor-piercing bullet of the 1930 model, when hit along the normal (P90 °), penetrates 7 mm armor from a distance of 400 m without failure, from a distance of 800 m - less than half, at a distance of 1000 m the armor does not break through at all, when the trajectory deviates from the normal by 15 ° from a distance of 400 m, through holes in 7-mm armor are obtained in 60% of cases, and with a deviation from the normal by 30 ° already from a distance of 250 m, the bullet does not penetrate the armor at all.
An armor-piercing bullet of 7.62 mm caliber penetrates:
The penetrating effect of a 5.6-mm bullet of a small-bore sports cartridge for side fire (muzzle velocity 330 m / s, distance 50 m):
Heavy plate body armor of the time of the Great Patriotic War, worn over two quilted jackets, holds a light rifle bullet even when fired at point-blank range.
The window pane shatters the rifle bullet. The fact is that the glass particles, acting like emery, when they meet the narrow nose of a rifle bullet, instantly "strip" the shell from it. The remaining fragments of the bullet fly along a changed unpredictable trajectory and do not guarantee hitting a target behind the glass. This phenomenon is observed when shooting from rifles and machine guns ammunition with pointed bullets. The narrow nose of the bullet at high speed abruptly takes on a large abrasive load and instantly collapses. This phenomenon is not observed in blunt pistol bullets and revolver revolver bullets flying at low subsonic speeds.
Therefore, when shooting at targets located behind glass, it is recommended to shoot either armor-piercing bullets or bullets with a steel core (with a silver nose).
At a distance of up to 800 m, the helmet can be pierced by all types of bullets, except for tracer bullets.
With the loss of bullet velocity, its penetrating effect decreases (Table 42):
Table 42
Loss of speed 7.62 mm bullet
ATTENTION. Tracer bullets, due to the burnout of the tracer composition, quickly lose mass, and with it their penetrating ability. At a distance of 200 m, the tracer bullet does not even penetrate a helmet.
The initial speed of sports small-caliber cartridges with lead bullets of various batches and names ranges from 280-350 m / s. The muzzle velocity of western small-caliber cartridges with sheathed and semi-sheathed bullets of various batches ranges from 380 to 550 m / s.
SNIPER CARTRIDGES
In sniper shooting, two types of cartridges are most preferable, specially designed for use in real combat conditions. The first of them is called "sniper" (photo 195). These cartridges are made with great care, not only with a uniform weight of powder charge and bullets of the same mass, but also with very precise observance of the geometric shape of the bullet, with a special soft liner material, with a thicker layer of tombak coating. "Sniper" cartridges have a very high accuracy of combat, not inferior to the accuracy of combat of special sports-target cartridges of the same caliber with a brass sleeve. The bullet of the "sniper" cartridge is not painted with anything in order to avoid changing the weight balance. These cartridges are specifically designed to defeat enemy personnel. Look at the longitudinal section of the bullet of this ammunition (photo 196). There is a void in the head of the bullet, and the hollow nose of the bullet serves as a ballistic tip-fairing. This is followed by a steel core and only then - lead casting. The center of gravity of such a bullet is slightly shifted back. When it hits dense tissue (bone), such a bullet turns sideways, rolls, then falls apart into the head (steel) and tail (lead) parts, which move inside the target independently and unpredictably, leaving the enemy no chance of survival. Hunters said that such ammunition successfully knocked down even a large animal.
Photo 195. "Sniper" cartridge on a fragment of packaging
Photo 196. Longitudinal section of the bullet of the "sniper" cartridge
1 - empty ballistic tip; 2 - steel core; 3 - lead filling; 4 - bevel of the core; 5 - hollow shank
Thanks to the steel core, the bullets of "sniper" cartridges have 25-30% higher armor penetration than conventional light bullets. Bullets of this type of ammunition have a streamlined shape of a heavy bullet of the 1930 g sample, but a weight equal to the weight of a light bullet is 9.9 g due to a steel core and a void in the tail section. This was specially conceived by the developers to give a light bullet useful qualities bullets heavy. Therefore, the trajectory of a bullet of "sniper" cartridges corresponds to table. 8 exceeding the average trajectories given in this manual and the manual for the SVD rifle.
As already mentioned, the bullets of "sniper" cartridges are not marked with anything (photo 197). The paper packs of these ammunition bear the inscription "sniper".
Photo 197. Bullet of the "sniper" cartridge
The second type of ammunition, intended for sniper shooting, has a bullet with a steel core, the head of which is painted in silver (photo 198). They are called that - bullets with a silver nose (bullet weight 9.6 g).
Photo 198. A bullet with a "silver" nose for shooting at lightly armored targets
The steel core of this bullet takes most its volume (photo 199).
Photo 199. Cross-section of a bullet for shooting at lightly armored targets:
1 - lead casting, 2 - steel core; 3 - lead jacket between the steel core and the shell
There is a lead filling in the head of the bullet for greater stability of the bullet in flight. Such ammunition is designed for sniper work on lightly armored and fortified targets. A bullet with a silver nose mark penetrates:
The longitudinal section shows that the cored bullets are streamlined as a heavy tapered shank bullet. But these bullets belong to the category of light (weight 9.6 g) because of the steel core, which is lighter than lead of the same volume. The ballistics of these bullets and the accuracy of the battle are practically the same as those of "sniper" cartridges, and when firing them, one should be guided by the same table of exceeding the average trajectories for the SVD rifle.
The above two types of ammunition were developed in relation to the SVD rifle, but their ballistics practically corresponds to table. 9 exceeding the average trajectories for the three-line rifle of the 1891-1930 model, given in this manual.
Specialized 7.62 mm "sniper" and "silver nose" cartridges, designed specifically for sniper shooting, are light in weight and lateral load, while having the same perfect aerodynamic shape as heavy bullets of the 1930 model, therefore their trajectory at a distance of up to 500 m it corresponds to the trajectory of a light bullet, and at a distance of 500 to 1300 m - to a trajectory of a heavy bullet. Therefore, in the table of exceeding the average trajectories for the SVD rifle, ballistic data for firing a light bullet are indicated, namely: "sniper" cartridges, "silver nose" and gross machine gun-rifle cartridges with a steel core.
Bullets of "sniper" cartridges are made light for increased action on a live target. The speed of a light bullet is faster than a heavy one. As is already known, a bullet hitting a live target at a speed of 700 m / s and higher causes a water hammer and an associated physiological shock, instantly incapacitating the target. Such an effect of a light bullet of a sniper cartridge on a target remains practically up to 400-500 m, after this distance the speed of the bullet is reduced by air resistance, but the damaging effect of the bullet of the "sniper" cartridge does not decrease from this. Why? Take a close look at the rip cut of this bullet. the steel core at the head has a slightly noticeable bevel right side up (see photo 196). This creates a slight overweight on one side of the bullet head. When rotating, this counterweight more and more brings the nose of the bullet to the side and it more and more acquires an unstable horizontal position. Therefore, the further the distance to the target, the more unstable the bullet becomes when approaching it. At firing distances of more than 400-500 m, a bullet of sniper cartridges, even when it hits soft tissues, turns sideways and, if it does not fall apart, starts tumbling, leaving minced meat behind.
With all this, the bullet of the "sniper" cartridge holds very well in the wind (as they say, "stands in the wind") and is guaranteed to maintain a stable position in flight at a firing distance of 200 m.
Accuracy of combat of "sniper" cartridges can be considered absolute. All the failures that occur when working with these cartridges can only be explained by the reduced quality of the barrel or the shooter's mistakes. The unique ballistic data of the above-described ammunition and its increased action on the target caused noticeable confusion among the NATO military during the last Balkan conflicts.
SELECTION OF AMMUNITION
In real combat practice, it is not always necessary to shoot ammunition made and designed specifically for sniper shooting. Sometimes you have to shoot with what is available. Galvanized bulk cartridges manufactured in pre-war, military and post-war time(1936-1956), often have an incorrect "oblique" landing of the bullet in the muzzle of the sleeve. These are the so-called "curved" cartridges, in which the bullet is slightly deflected to the side from the common axis of the cartridge case - the bullet. This "curved" bullet landing is noticeable to the eye. Even the unevenness of the landing of the bullet in the sleeve in depth is noticeable to the eye: very often the bullets are planted either too deeply, or protrude excessively.
Bullets with a "oblique" landing will also go along the barrel in an "oblique" manner, and therefore they will not provide firing accuracy. Bullets with unequal fit will give unequal bore pressure and indicate vertical spread. By visual inspection, such cartridges are discarded and given to machine gunners. Of course, bulk cartridges with light bullets of the 1908-1930 model. will have a much wider spread than sniper or sports-target, but in war it is better than nothing.
You can shoot any cartridges, new in appearance, without severe abrasions, scratches, dents, rust on the surface.
The worn cartridges indicate that they were carried in pockets and pouches for a very long time and it is not known under what circumstances. This ammunition may be soaked and may not fire.
Do not use cartridges that have even minor dents on the sleeves. It is not that such ammunition does not go into the chamber; if necessary, they can be driven there by force. The fact is that the dent, straightening under devilish pressure, strikes the chamber wall with great force and can easily break it. There have been such cases. Do not use cartridges with rusty casings and rusty bullets. Rusty bullet shells can break apart and deform bullet fragments fly in unpredictable directions. A rusty sleeve can be easily torn apart. In this case, it happens that the remnants of the case do not just stick to the chamber, but are tightly welded to it. It happens that in this case, when gases blow back, the bolt is welded to the receiver and, in addition, the shooter receives a strong gas blow in the face with the risk of eye damage.
You cannot use cartridges from the first half of the 30s and earlier. Such ammunition often detonates; it happens that at the same time the trunk is blown to shreds, tearing off the arrow with the fingers of the left hand.
You cannot carry cartridges in leather pouches and cartridge belts - only in canvas or tarpaulin. From contact with the skin, the metal of the clad ammunition becomes green and rusty.
And, of course, you can't lubricate the ammunition - they don't fire after that. With the force of surface tension, even the thickest grease sooner or later penetrates into the cartridge and envelops the primer and powder charges, which then do not work. To protect the cartridges from moisture, it is allowed to lubricate them with a thin layer of lard, and such ammunition is recommended to be used first and foremost.
Do not forget that tracer bullets damage the barrel and, at a distance of 200 m (and even less), do not even pierce a helmet. Use tracer bullets as needed and for target designation.
If possible, calibrate the bulk cartridges by the diameter of the bullet and select for firing cartridges with bullets of the same diameter and depth in the sleeve. Snipers of the old formation, gross cartridges (and even target ones) must weigh and reject those that have deviations in total weight... If possible, you should do the same. With all this, you will dramatically increase the accuracy of the fight of your barrel.
Always have a few armor-piercing incendiary and tracer rounds. Combat necessity may require their use under the most unexpected circumstances.
Do not use cartridges with the primer protruding from the bottom of the sleeve. When the shutter is closed, such a cartridge may trigger prematurely.
Do not use cartridges that are corroded or cracked on the primer. Such a primer can be pierced by a drummer.
If there is a misfire and this cartridge is not your last, throw it away without regret. You cannot "click" on this cartridge a second time. A strong rifle striker can pierce the primer, and the gas stream then hits the shooter's face with the power of a boxing fist without a glove. Once, in his youth, the author did not believe in this until he received such a terrible gas slap in the face. The feeling was as if the head came off and everything else exists by itself.
Very rare, but still very dangerous phenomenon called a lingering shot. It happens that a gunpowder that has gotten into lumps or damp does not ignite immediately, but after a while. Therefore, in the event of a misfire, never rush to open the shutter immediately. After a misfire, count to ten, and if the shot does not occur, open the bolt sharply and throw out the unused cartridge. The author witnessed a case when a young cadet, unable to withstand the required 5-6 seconds after a misfire, pulled the bolt towards himself, the cartridge flew out, fell under the feet of the instructor and exploded. No harm done. But if this cartridge worked at the moment the shutter was opened, the consequences would be dire.
Bullet speed is one of the most important characteristics of a weapon. Its value depends on a number of factors. These include the mass of the bullet, the length of the barrel of the weapon and the energy transferred to the bullet, which depends on the mass of the powder charge. Moving along the bore under the influence of powder gases, the bullet reaches maximum speed a few centimeters from the muzzle. This speed is called the initial speed and is indicated in the characteristics of the weapon. Naturally, for each weapon model, the bullet speed will be different. In this regard, it is possible to answer the question of how fast a bullet flies, only by grading small arms according to its categories.
Pistols, revolvers, submachine guns
This category of weapons is characterized by a short barrel (it is so often called short-barreled). It uses, as a rule, pistol cartridges equipped with a relatively small charge of gunpowder. In this regard, the muzzle velocity is relatively low and averages 300-500 m / s. So, the initial bullet velocity in the Makarov pistol (PM) is 315 m / s, in the TT pistol - 420 m / s.
Assault rifles, machine guns
In this category of weapons, the so-called intermediate cartridge is mainly used. The muzzle velocity of a bullet can reach an average of 700-1000 m / s. For example, the muzzle velocity in a Kalashnikov assault rifle is 720 m / s.
Rifles, sniper rifles, machine guns
In such weapons, reinforced ammunition is used, and this factor has a decisive influence on how fast the bullet flies. Its value can reach 1500 m / s. So, the muzzle velocity of the famous Mosin rifle, model 1891/30. was equal to 865 m / s, the bullet speed in the Dragunov sniper rifle is 830 m / s, and the Kalashnikov light machine gun (RPK) fires bullets with an initial speed of 960 m / s.
In chapter Gold fund when asked what is the speed of a bullet? given by the author ***
the best answer is The bullet speed depends on the type of weapon and for modern firearms it varies on average from 300 to 1000 m / s.
There is one very simple method for measuring bullet velocity:
A heavy piece of wood suspended by a thread (four, one thread from each end).
Measurement technique: you shoot at a piece of wood, you look at how much it deviates, you count.
Vbullets = (2 * sin ((90 * l) / (Pi * R)) * sqrt (g * R) * (m + M)) / m
where:
l - how much a piece of wood deviates when a bullet hits, m
Pi - 3.14159265356 ...
R - suspension thread length, m - at least one meter
g - acceleration due to gravity, 9.81 m / s2
m - bullet mass
M - mass of a piece of wood
Answer from 2 answers[guru]
Hey! Here is a selection of topics answering your question: What is the velocity of a bullet?
Answer from Sieg Fried[guru]
About 370 meters per second ...
Answer from Paul[guru]
It depends on which barrel and which bullet ...
Answer from User deleted[newbie]
x ... you will catch up !!
Answer from Yergey Terentyev[guru]
of course it depends on the weapon and the cartridge. I know for sure that the speed of a bullet (ordinary, with a lead core) fired from the SVD is 920-940 ms.
Answer from 1
[guru]
different well, somewhere 400 km per hour
Answer from !!
[active]
okolo 900 m.v sekundu
Answer from User deleted[newbie]
If it (the bullet) is already well .. ne, then it is not high ...
Answer from User deleted[guru]
if from Kalash = 750m / sec. From another weapon, sorry ...
Answer from D.M.[guru]
In the memoirs of a pilot of the First World War, a case is described when in the air he saw a bullet flying nearby,
obviously at the end. The aircraft's speed at this time was about 50 km. in hour.
Answer from Ѐuslan Ivanov[active]
For pistols, the bullet velocity is within the speed of sound (340m / s), for the effective use of silencers
AK-47 = 750 ms
AK-74 = 900 ms
SVD = 840
PM = 315
Answer from Sergio Noise[newbie]
This is influenced by the speed of the bullet: the quality of the powder (the smaller the particles, the better) humidity, temperature environment.. And a number of other factors.
Answer from Plovezz[active]
do not be afraid of the sounds of a shot in the war, you will not hear your bullet ...
INITIAL BULLET SPEED
The initial velocity is one of the most important characteristics of the weapon's combat properties. With an increase in the initial speed, the range of the bullet, the range of a direct shot, the lethal and penetrating action of the bullet increase, and the influence of external conditions on its flight decreases. In particular, the faster the bullet flies, the less it is blown away by the wind. The value of the initial velocity of the bullet must be indicated in the firing tables and in the combat characteristics of the weapon.
The magnitude of the initial velocity of the bullet depends on the length of the barrel, the weight of the bullet, the weight, temperature and moisture content of the powder charge, the shape and size of the powder grains, and the loading density.
The longer the barrel, the longer the propellant gases act on the bullet and the greater (within the known technical limits, see earlier) the initial velocity.
With a constant barrel length and constant weight of the powder charge, the lower the bullet weight, the higher the initial velocity.
A change in the weight of the powder charge leads to a change in the amount of powder gases, and, consequently, to a change in the value of the maximum pressure in the bore and the initial velocity of the bullet. The more gunpowder, the more pressure and the more the bullet accelerates along the barrel.
The length of the barrel and the weight of the powder charge are balanced according to the above graphs (schemes 111, 112) of internal fire processes in the rifle barrel when designing and assembling weapons to the most rational dimensions.
As the external temperature rises, the combustion rate of the propellant increases, and therefore the maximum pressure and initial velocity increase. As the outside temperature drops, the initial speed decreases. In addition, as the outside temperature changes, the barrel temperature also changes, and more or less heat is needed to heat it up. And this, in turn, affects the change in pressure in the barrel and, accordingly, the initial velocity of the bullet.
One of the old snipers in the memory of the author in a specially sewn bandolier carried a dozen rifle cartridges under his arm. When asked what it matters, the elderly instructor replied, "It is very important. You and I were both shooting at 300 meters, but your spread went vertically up and down, but I did not. Because the gunpowder is in my cartridges. warmed up to 36 degrees under the arm, and yours in the pouch froze to minus 15 (it was in winter). You shot the rifle in the fall at plus 15, a total difference of 30 degrees. You shoot with frequent fire, and your barrel is hot, so you have the first bullets go lower, and the latter - higher. And all the time I shoot gunpowder of the same temperature, so everything flies as expected. "
An increase (decrease) in the initial speed causes an increase (decrease) in the firing range. The differences in these values are so significant that in the practice of hunting shooting from smoothbore guns, summer and winter barrels of different lengths are used (winter barrels are usually 7-8 cm longer than summer ones) to achieve the same shooting range. In sniper practice, range corrections for air temperature must be made according to the corresponding tables (see earlier).
With an increase in the moisture content of the powder charge, its combustion rate decreases and, accordingly, the pressure in the barrel and the initial velocity drop.
The combustion rate of the powder is directly proportional to the surrounding pressure. In the open air, the combustion rate of smokeless rifle powder is approximately 1 m / s, and in the closed space of the chamber and barrel, due to the pressure increase, the combustion rate of the powder increases and reaches several tens of meters per second.
The ratio of the weight of the charge to the volume of the sleeve with the bullet inserted (the combustion chamber of the charge) is called the loading density. The more the gunpowder is "rammed" in the sleeve, which occurs with an overdose of gunpowder or a deep landing of the bullet, the more the pressure and combustion rate increase. This sometimes leads to a sharp jump in pressure and even to the detonation of the powder charge, which can lead to rupture of the barrel. The loading density is made according to complex engineering calculations and for a domestic rifle cartridge is 0.813 kg / dm3. With a decrease in the loading density, the burning rate decreases, the time for the bullet to travel along the barrel increases, which, paradoxically, leads to a rapid overheating of the weapon. For all these reasons, reloading live ammunition is prohibited!
These breathtaking photos capture the moment a bullet escapes from the barrel at over 365 meters per second. The author of the project is the Finnish photographer Herra Kuulapaa, who has been perfecting the unusual high-speed shooting technique for the last 7 years. In addition to the beautiful visual effect, his work has a scientific background.
(20 photos total)
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1. Seven years ago, a group of amateur photographers launched an initiative that later grew into a project that helps firearms manufacturers to better understand the processes of fire at the moment a shot is fired. This allows companies to improve their products. Pictured is a modified Austrian Glock.
2. “Sports shooting enthusiasts all over the world are eager to know what happens in milliseconds at the moment a bullet leaves the bore. Our new method allowed us to obtain detailed 3D images of a projectile fired from a gunshot. You can see 3D images of the explosion and the flow of powder gas, ”says Kuulapaa.
3. In the photo: Bullets fly at a speed of 1,280 km / h
4. None of the moments shown in the pictures can be seen with the naked eye, since the action takes place in hundredths of a second. But it's not easy beautiful pictures with their help, weapon manufacturers receive information on gas flow and temperature distribution during a shot to improve their products.
5. The bullet leaves the barrel of the weapon when fired in milliseconds.
6. Many shots show impressive flash when fired.
7. The photographer admits that he often accidentally damages his equipment and lenses, trying to capture the right moment.
8. Shot from the Smith & Wesson Model 500, the most powerful mass-produced revolver to date
9. Mass of the giant sky of cartridges - 2 kg 60 g. Smith and Wesson model 500 in the film "Return of the Hero" with Schwarzenegger
10. On the collage: A sequence of shots showing the projection of a bullet from a rifle.
11. Shot by our cartridge 7.62 × 39 mm from American rifle AR-15. Considered the third most powerful submachine gun in the world
12. "Our latest achievements are 3D-shooting of a shot, where you can see a three-dimensional picture."
13. A cloud of gases when fired
14. The initial moment of a shot from an AR-15 rifle
15. The bullet takes off at a speed of 3,050 km / h, which is much faster than when fired from a pistol.