5.45x39mm
Encyclopedia
The Soviet 5.45×39mm cartridge
is a rimless
bottlenecked rifle
cartridge
. It was introduced into service in 1974 for use with the new AK-74
assault rifle
. It gradually supplemented then largely replaced the 7.62x39mm round in service.
The 5.45×39mm is an example of an international tendency towards relatively small sized light weight military service cartridges. Cartridges like the Russian 5.45×39mm, 5.56×45mm NATO and Chinese 5.8×42mm allow a soldier to carry more ammunition for the same weight compared to their larger and heavier predecessor cartridges and produce relatively low bolt thrust
and free recoil
, favouring light weight arms design and automatic fire accuracy.
bullets that have a somewhat complex construction. The 3.2 g (2.880028800288E-07 gr) boattail projectile has a gilding-metal-clad jacket. The unhardened steel core is covered by a thin lead
coating which does not fill the entire point end, leaving a hollow cavity inside the nose. The bullet is cut to length during the manufacturing process to give the correct weight. The 5N7 uses a boattail design to reduce drag
and there is a small lead plug crimped in place in the base of the bullet. The lead plug, in combination with the air space at the point of the bullet, has the effect of moving the bullet's center of gravity to the rear; the hollow air space also makes the bullet's point prone to deformation when the bullet strikes anything solid, inducing yaw. The brown-lacquered steel case is Berdan-primed. Its 39.37 mm (1.55 in) length makes it slightly longer than the 7.62×39mm case which measures exactly 38.6 mm (1.52 in). The primer has a copper cup and is sealed with a heavy red lacquer. The propellant charge is a ball powder with similar burning characteristics to the WC 844 powder used in 5.56×45mm NATO ammunition. The 5N7 cartridge weight is 10.75 g (9.67509675096751E-07 gr).
Tests indicate the free recoil
energy delivered by the 5.45X39mm AK-74
assault rifle is 3.39 J (2.5 ft-lb), compared to 6.44 J (4.75 ft-lb) delivered by the 5.56×45mm NATO in the M16
assault rifle and 7.19 J (5.3 ft-lb) delivered by the 7.62x39mm in the AKM
assault rifle.
Military 5.45×39mm ammunition was produced in the former Soviet Union, German Democratic Republic and Yugoslavia, and is produced in Bulgaria, Poland and Romania. In the former Soviet Union this ammunition is produced in Russia, Kyrgyzstan, Uzbekistan and the Ukraine.
H2O) cartridge case capacity.
5.45×39mm maximum C.I.P. cartridge dimensions.
Americans would define the shoulder angle at ≈ 20.3°. The common rifling
twist rate for this cartridge is 255 mm (1 in 10 inches), 4 grooves, Ø lands = 5.40 mm, Ø grooves = 5.60 mm, land width = 2.60 mm and the primer type
is either berdan or small rifle.
According to the official C.I.P. (Commission Internationale Permanente Pour L'Epreuve Des Armes A Feu Portatives) guidelines the 5.45×39mm case can handle up to 380 MPa (55,114.3 psi) piezo pressure. In C.I.P. regulated countries every rifle cartridge combo has to be proofed at 125% of this maximum C.I.P. pressure to certify for sale to consumers.
and cavitation
of projectiles was primarily responsible for tissue damage. Martin Fackler
conducted a study with an AK-74 assault rifle using live pigs and ballistic gelatin
demonstrating that the 5.45×39mm round does not reliably fragment or cause unusual amounts of tissue disruption. Most organs and tissue were too flexible to be severely damaged by the temporary cavity effect caused by yaw and cavitation of a projectile. With the 5.45 mm bullet, tumbling produced a temporary cavity twice, at depths of 100 and 350 mm. This is comparable to modern 7.62×39mm ammunition and to (non-fragmenting) 5.56 mm ammunition.
The 7N6 bullet has a 1.43 g (1.2870128701287E-07 gr) steel rod penetrator. Since 1987 this penetrator is hardened to 60 HRC
. The latter 7N6 cartridge can penetrate a 6 mm thick St3 steel plate at 300 m and 6Zh85T body armour at 80 m. 7N6 bullets have a red identification ring above the cartridge neck.
The 7N10 "improved penetration" cartridge was introduced in 1992. The size of the steel penetrator was increased to 1.76 g (1.5840158401584E-07 gr) and the lead plug in front of it was discarded.
In 1994 the 7N10 design was improved by filling the air space with lead. Upon impacting a hard target, soft lead is pressed sideways by the steel penetrator, tearing the jacket.
The 7N10 cartridge replaced the previous variants as standard Russian service round and can penetrate a 16 mm thick St3 steel plate at 300 m and 6Zh85T body armour at 200 m. 7N10 bullets have a violet/purple identification ring above the cartridge neck.
The 7N22 armour-piercing bullet, introduced in 1998, has a 1.75 g (1.5750157501575E-07 gr) sharp-pointed steel penetrator and retains the soft lead plug in the nose for jacket discarding. 7N22 bullets can be identified by their red identification ring above the cartridge neck and a black tip.
The recent 7N24 "super-armor-piercing" cartridge has a penetrator made of tungsten carbide
. The 7N24 round is loaded with a a 4.15 g (3.7350373503735E-07 gr) projectile containing a 2.1 g (1.890018900189E-07 gr) penetrator which is fired with a muzzle velocity of 840 m/s (2,756 ft/s) yielding 1464 joule muzzle energy.
7T3 and 7T3M were developed. These bullets can be identified by their green marked tips. The 3.23 g (50 gr) tracer projectile has a shorter ogival profile and for 7T3 ammunition burns out to 800 m (874.9 yd) and for 7T3M ammunition ignites at 50 m (54.7 yd) burning out to 850 m (929.6 yd).
For instruction purposes the 7H4 training or dummy cartridge (which has longitudinal grooves) was developed.
The 7U1 subsonic cartridge weight is 11 g (9.90009900099001E-07 gr) and is loaded with a 5.2 g (4.68004680046801E-07 gr) projectile which is fired with a muzzle velocity of 303 m/s (994 ft/s) yielding 239 joule muzzle energy. Accuracy of fire at 100 m (109 yd) (R50) is 35 mm (1.4 in)
Cartridge (firearms)
A cartridge, also called a round, packages the bullet, gunpowder and primer into a single metallic case precisely made to fit the firing chamber of a firearm. The primer is a small charge of impact-sensitive chemical that may be located at the center of the case head or at its rim . Electrically...
is a rimless
Rim (firearms)
A rim is an external flange that is machined, cast, molded, stamped or pressed around the bottom of a firearms cartridge. The rim may serve a number of purposes, the most common being as the place for the extractor to engage...
bottlenecked rifle
Rifle
A rifle is a firearm designed to be fired from the shoulder, with a barrel that has a helical groove or pattern of grooves cut into the barrel walls. The raised areas of the rifling are called "lands," which make contact with the projectile , imparting spin around an axis corresponding to the...
cartridge
Cartridge (firearms)
A cartridge, also called a round, packages the bullet, gunpowder and primer into a single metallic case precisely made to fit the firing chamber of a firearm. The primer is a small charge of impact-sensitive chemical that may be located at the center of the case head or at its rim . Electrically...
. It was introduced into service in 1974 for use with the new AK-74
AK-74
The AK-74 is an assault rifle developed in the early 1970s in the Soviet Union as the replacement for the earlier AKM...
assault rifle
Assault rifle
An assault rifle is a selective fire rifle that uses an intermediate cartridge and a detachable magazine. Assault rifles are the standard infantry weapons in most modern armies...
. It gradually supplemented then largely replaced the 7.62x39mm round in service.
The 5.45×39mm is an example of an international tendency towards relatively small sized light weight military service cartridges. Cartridges like the Russian 5.45×39mm, 5.56×45mm NATO and Chinese 5.8×42mm allow a soldier to carry more ammunition for the same weight compared to their larger and heavier predecessor cartridges and produce relatively low bolt thrust
Bolt thrust
Bolt thrust or breech pressure is a term used in internal ballistics and firearms that describes the amount of rearward force exerted by the propellant gases on the bolt or breech of a firearm action or breech when a projectile is fired...
and free recoil
Free recoil
This article is about the energy produced by small arms when discharged. For other uses, go to Recoil Free recoil is a vernacular term or jargon for recoil energy...
, favouring light weight arms design and automatic fire accuracy.
History
The Russian original military issue 5N7 cartridge variant introduced in 1974 are loaded with full metal jacketFull metal jacket bullet
A full metal jacket is a bullet consisting of a soft core encased in a shell of harder metal, such as gilding metal, cupronickel or less commonly a steel alloy. This shell can extend around all of the bullet, or often just the front and sides with the rear left as exposed lead...
bullets that have a somewhat complex construction. The 3.2 g (2.880028800288E-07 gr) boattail projectile has a gilding-metal-clad jacket. The unhardened steel core is covered by a thin lead
Lead
Lead is a main-group element in the carbon group with the symbol Pb and atomic number 82. Lead is a soft, malleable poor metal. It is also counted as one of the heavy metals. Metallic lead has a bluish-white color after being freshly cut, but it soon tarnishes to a dull grayish color when exposed...
coating which does not fill the entire point end, leaving a hollow cavity inside the nose. The bullet is cut to length during the manufacturing process to give the correct weight. The 5N7 uses a boattail design to reduce drag
Drag (physics)
In fluid dynamics, drag refers to forces which act on a solid object in the direction of the relative fluid flow velocity...
and there is a small lead plug crimped in place in the base of the bullet. The lead plug, in combination with the air space at the point of the bullet, has the effect of moving the bullet's center of gravity to the rear; the hollow air space also makes the bullet's point prone to deformation when the bullet strikes anything solid, inducing yaw. The brown-lacquered steel case is Berdan-primed. Its 39.37 mm (1.55 in) length makes it slightly longer than the 7.62×39mm case which measures exactly 38.6 mm (1.52 in). The primer has a copper cup and is sealed with a heavy red lacquer. The propellant charge is a ball powder with similar burning characteristics to the WC 844 powder used in 5.56×45mm NATO ammunition. The 5N7 cartridge weight is 10.75 g (9.67509675096751E-07 gr).
Tests indicate the free recoil
Free recoil
This article is about the energy produced by small arms when discharged. For other uses, go to Recoil Free recoil is a vernacular term or jargon for recoil energy...
energy delivered by the 5.45X39mm AK-74
AK-74
The AK-74 is an assault rifle developed in the early 1970s in the Soviet Union as the replacement for the earlier AKM...
assault rifle is 3.39 J (2.5 ft-lb), compared to 6.44 J (4.75 ft-lb) delivered by the 5.56×45mm NATO in the M16
M16 rifle
The M16 is the United States military designation for the AR-15 rifle adapted for both semi-automatic and full-automatic fire. Colt purchased the rights to the AR-15 from ArmaLite, and currently uses that designation only for semi-automatic versions of the rifle. The M16 fires the 5.56×45mm NATO...
assault rifle and 7.19 J (5.3 ft-lb) delivered by the 7.62x39mm in the AKM
AKM
The AKM is a 7.62mm assault rifle designed by Mikhail Kalashnikov. It is an upgraded version of the AK-47 rifle and was developed in the 1950s....
assault rifle.
Military 5.45×39mm ammunition was produced in the former Soviet Union, German Democratic Republic and Yugoslavia, and is produced in Bulgaria, Poland and Romania. In the former Soviet Union this ammunition is produced in Russia, Kyrgyzstan, Uzbekistan and the Ukraine.
Cartridge dimensions
The 5.45×39mm has 1.75 ml (27 grainsGrain (measure)
A grain is a unit of measurement of mass that is nominally based upon the mass of a single seed of a cereal. From the Bronze Age into the Renaissance the average masses of wheat and barley grains were part of the legal definition of units of mass. However, there is no evidence of any country ever...
H2O) cartridge case capacity.
5.45×39mm maximum C.I.P. cartridge dimensions.
Americans would define the shoulder angle at ≈ 20.3°. The common rifling
Rifling
Rifling is the process of making helical grooves in the barrel of a gun or firearm, which imparts a spin to a projectile around its long axis...
twist rate for this cartridge is 255 mm (1 in 10 inches), 4 grooves, Ø lands = 5.40 mm, Ø grooves = 5.60 mm, land width = 2.60 mm and the primer type
Percussion cap
The percussion cap, introduced around 1830, was the crucial invention that enabled muzzleloading firearms to fire reliably in any weather.Before this development, firearms used flintlock ignition systems which produced flint-on-steel sparks to ignite a pan of priming powder and thereby fire the...
is either berdan or small rifle.
According to the official C.I.P. (Commission Internationale Permanente Pour L'Epreuve Des Armes A Feu Portatives) guidelines the 5.45×39mm case can handle up to 380 MPa (55,114.3 psi) piezo pressure. In C.I.P. regulated countries every rifle cartridge combo has to be proofed at 125% of this maximum C.I.P. pressure to certify for sale to consumers.
Wounding effects
Early ballistics tests done demonstrated a pronounced tumbling effect with high speed cameras. Some Western authorities believed this bullet was designed to tumble in flesh to increase wounding potential. At the time, it was believed that yawingFlight dynamics
Flight dynamics is the science of air vehicle orientation and control in three dimensions. The three critical flight dynamics parameters are the angles of rotation in three dimensions about the vehicle's center of mass, known as pitch, roll and yaw .Aerospace engineers develop control systems for...
and cavitation
Cavitation
Cavitation is the formation and then immediate implosion of cavities in a liquidi.e. small liquid-free zones that are the consequence of forces acting upon the liquid...
of projectiles was primarily responsible for tissue damage. Martin Fackler
Martin Fackler
Dr. Martin L. Fackler is a retired Colonel in the US Army's Medical Corps, he was a battlefield surgeon, and the head of the Wound Ballistics Laboratory for the US Army’s Medical Training Center, Letterman Institute....
conducted a study with an AK-74 assault rifle using live pigs and ballistic gelatin
Ballistic gelatin
Ballistic Gelatin is a testing medium scientifically correlated to swine muscle tissue , in which the effects of bullet wounds can be simulated. It was developed and improved by Martin Fackler and others in the field of wound ballistics. Ballistic gelatin is a solution of gelatin powder in water...
demonstrating that the 5.45×39mm round does not reliably fragment or cause unusual amounts of tissue disruption. Most organs and tissue were too flexible to be severely damaged by the temporary cavity effect caused by yaw and cavitation of a projectile. With the 5.45 mm bullet, tumbling produced a temporary cavity twice, at depths of 100 and 350 mm. This is comparable to modern 7.62×39mm ammunition and to (non-fragmenting) 5.56 mm ammunition.
Enhanced penetration cartridges
As body armor saw increasing use in militaries, the original 5N7 standard service cartridge bullet construction was changed several times to improve penetration. This resulted in the 7N6, 7N10, 7N22 and 7N24 cartridge 5.45×39mm variants.The 7N6 bullet has a 1.43 g (1.2870128701287E-07 gr) steel rod penetrator. Since 1987 this penetrator is hardened to 60 HRC
Rockwell scale
The Rockwell scale is a hardness scale based on the indentation hardness of a material. The Rockwell test determines the hardness by measuring the depth of penetration of an indenter under a large load compared to the penetration made by a preload. There are different scales, denoted by a single...
. The latter 7N6 cartridge can penetrate a 6 mm thick St3 steel plate at 300 m and 6Zh85T body armour at 80 m. 7N6 bullets have a red identification ring above the cartridge neck.
The 7N10 "improved penetration" cartridge was introduced in 1992. The size of the steel penetrator was increased to 1.76 g (1.5840158401584E-07 gr) and the lead plug in front of it was discarded.
In 1994 the 7N10 design was improved by filling the air space with lead. Upon impacting a hard target, soft lead is pressed sideways by the steel penetrator, tearing the jacket.
The 7N10 cartridge replaced the previous variants as standard Russian service round and can penetrate a 16 mm thick St3 steel plate at 300 m and 6Zh85T body armour at 200 m. 7N10 bullets have a violet/purple identification ring above the cartridge neck.
The 7N22 armour-piercing bullet, introduced in 1998, has a 1.75 g (1.5750157501575E-07 gr) sharp-pointed steel penetrator and retains the soft lead plug in the nose for jacket discarding. 7N22 bullets can be identified by their red identification ring above the cartridge neck and a black tip.
The recent 7N24 "super-armor-piercing" cartridge has a penetrator made of tungsten carbide
Tungsten carbide
Tungsten carbide is an inorganic chemical compound containing equal parts of tungsten and carbon atoms. Colloquially, tungsten carbide is often simply called carbide. In its most basic form, it is a fine gray powder, but it can be pressed and formed into shapes for use in industrial machinery,...
. The 7N24 round is loaded with a a 4.15 g (3.7350373503735E-07 gr) projectile containing a 2.1 g (1.890018900189E-07 gr) penetrator which is fired with a muzzle velocity of 840 m/s (2,756 ft/s) yielding 1464 joule muzzle energy.
Tracer cartridges
Besides that the tracer cartridgesTracer ammunition
Tracer ammunition are bullets that are built with a small pyrotechnic charge in their base. Ignited by the burning powder, the phosphorus tail burns very brightly, making the projectile visible to the naked eye...
7T3 and 7T3M were developed. These bullets can be identified by their green marked tips. The 3.23 g (50 gr) tracer projectile has a shorter ogival profile and for 7T3 ammunition burns out to 800 m (874.9 yd) and for 7T3M ammunition ignites at 50 m (54.7 yd) burning out to 850 m (929.6 yd).
Training and instruction cartridges
For training purposes the blank cartridges 7H3, 7H3M and 7Kh3 were developed. These round have a hollow white plastic imitation projectile. When these training rounds are used, the barrel of the gun is fitted at the muzzle with a Blank Fire Adapter to produce a gas pressure build-up for cycling the gun, as well as a breakup aid for their plastic projectiles.For instruction purposes the 7H4 training or dummy cartridge (which has longitudinal grooves) was developed.
Special purpose cartridges
For special purposes the 7U1 subsonic cartridge with a black and green painted meplat and CAP cartridge for underwater were developed.The 7U1 subsonic cartridge weight is 11 g (9.90009900099001E-07 gr) and is loaded with a 5.2 g (4.68004680046801E-07 gr) projectile which is fired with a muzzle velocity of 303 m/s (994 ft/s) yielding 239 joule muzzle energy. Accuracy of fire at 100 m (109 yd) (R50) is 35 mm (1.4 in)
Basic specifications
| Cartridge designation | 7N6 | 7N10 | 7N22 | 7T3 (tracer) | 7Kh3 (training) |
|---|---|---|---|---|---|
| Cartridge weight | 10.5 g (9.45009450094501E-07 gr) | 10.7 g (9.63009630096301E-07 gr) | 10.75 g (9.67509675096751E-07 gr) | 10.3 g (9.27009270092701E-07 gr) | 6.65 g (5.98505985059851E-07 gr) |
| Bullet weight | 3.43 g (3.0870308703087E-07 gr) | 3.62 g (3.2580325803258E-07 gr) | 3.68 g (3.3120331203312E-07 gr) | 3.23 g (2.9070290702907E-07 gr) | 0.24 g (2.160021600216E-08 gr) |
| Muzzle velocity | 880 m/s (2,887 ft/s) | 880 m/s (2,887 ft/s) | 890 m/s (2,920 ft/s) | 883 m/s (2,897 ft/s) | |
| Muzzle energy | 1328 joule | 1402 joule | 1457 joule | 1259 joule | |
| Accuracy of fire at 300 m (328 yd) (R50) |
75 mm (3 in) | 90 mm (3.5 in) | 90 mm (3.5 in) | 140 mm (5.5 in) | |
- R50 at 300 m (328 yd) means the closest 50 percent of the shot group will all be within a circle of the mentioned diameter at 300 m (328 yd).
- The twist rate used in the AK-74M assault rifle that has been adopted as the new service rifleService rifleThe service rifle of a given army or armed force is that which it issues as standard to its soldiers. In modern forces, this is typically a highly versatile and rugged assault rifle suitable for use in nearly all theatres and environments...
of the Russian Federation in 1991 is 200 mm (7.87 in).
External links
- Fackler ballistics study
- Terminal Ballistics Study - Bosnia - Military Medicine/December 2001
- Photos of various different types of 5.45×39mm ammunition
- 5.45x39mm cartridges
- Assault Rifles and Their Ammunition: History and Prospects by Anthony G. Williams, Online Article, October 21, 2006