7.62x39mm

7.62x39mm
Lateral view of a steel-cased 7.62x39mm FMJ cartridge.
Type	Rifle
Place of origin	Soviet Union
Service history
In service	1944–present
Used by	Soviet Union, Warsaw Pact, People's Republic of China, Cambodia, North Korea, Vietnam, Finland, Venezuela, numerous others
Production history
Designed	1943
Produced	1943–present
Specifications
Case type	Rimless, bottleneck
Bullet diameter	7.92 mm (0.312 in)
Neck diameter	8.60 mm (0.339 in)
Shoulder diameter	10.07 mm (0.396 in)
Base diameter	11.35 mm (0.447 in)
Rim diameter	11.35 mm (0.447 in)
Rim thickness	1.50 mm (0.059 in)
Case length	38.70 mm (1.524 in)
Overall length	56.00 mm (2.205 in)
Rifling twist	240 mm (1 in 9.45 in)
Primer type	Berdan or Boxer Small Rifle or Boxer Large Rifle
Maximum pressure	355.00 MPa (51,488 psi)
Filling	SSNF 50 powder
Filling weight	24.7 gr
Ballistic performance
Bullet weight/type	Velocity	Energy
123 gr (8.0 g) Full Metal Jacket	720 m/s (2,400 ft/s)	2,045 J (1,508 ft·lbf)
154 gr (10.0 g) Spitzer SP	641.3 m/s (2,104 ft/s)	2,059 J (1,519 ft·lbf)
Source: Chuck Hawks[1] Wolf Ammo[2] Omar

The 7.62x39mm rifle cartridge was designed during World War II and first used in the SKS carbine by the Soviet Union. Use of the cartridge is widespread by both militaries and civilians. This is due primarily to the proliferation of the SKS and AK-47 pattern rifles during the 20th century.

The cartridge was likely influenced by a variety of foreign developments, especially the pre-war German GeCo, 7.75x39mm experimental round,^[3] and possibly by the late-war German 7.92x33mm Kurz ("Kurz" meaning "short" in German). Shortly after the war, the world's most recognized military pattern rifle was designed for this cartridge: the AK-47. The cartridge remained the Soviet standard until the 1970s, and is still one of the most common intermediate rifle cartridges used around the world. It was superseded by the 5.45x39mm cartridge which is used by the current issue AK-74.

The cartridge produces significant wounding (including remote wounding effects known as hydrostatic shock) in cases where the bullet tumbles and fragments in tissue,^[4] but produces relatively minor wounds in cases where the bullet exits before beginning to yaw.^[5][6] In the absence of yaw, the M43 load can pencil through lung tissue with relatively little injury.^[7] Even in the absence of yaw and a large temporary cavity, a hit to the shoulder can produce significant lung hemorrhaging attributed to stress wave transmission.^[8] Indirect injuries can be common with hits to the abdomen and may be attributed to the explosive effects of temporary cavitation.^[9]

History

Oblique view of a steel-cased 7.62x39mm FMJ cartridge.

7.62x39 shown along side other cartridges. From left to right: 30-06, 7.62x39, .454 Casull, .45 Colt, .357 Magnum, .38 Special, .45 ACP, 9mm, .380, .22 Long Rifle

The original Soviet M43 bullets are boat-tail bullets with a copper-plated steel jacket, a large steel core, and some lead between the core and the jacket. The cartridge itself consists of a berdan-primed, highly tapered (usually steel) case which seats the bullet and contains the powder charge. The taper makes it very easy to feed and extract the round, since there is little contact with the chamber walls until the round is fully seated. This taper is what causes the AK-47 to have distinctively curved magazines (helping to distinguish AK-47s from AK-74s, which feed from a much straighter magazine). While the bullet design has gone through a few redesigns, the cartridge itself remains largely unchanged.

M43

Although the new cartridge represented a great leap forward from previous designs, the initial bullet design was flawed. The complete solidity of the M43 projectile causes its only drawback—it is very stable, even while traversing tissue. It begins to yaw only after traversing nearly 30 cm (12 in) of tissue. This greatly reduces the wounding effectiveness of the projectile against humans. Dr. Martin Fackler noted that the wounds from the M43 round were comparable to that of a small handgun round using non-expanding bullets. Unless the round struck something vital, the wound was usually non-fatal, small and quick to heal.

M67

In the 1960s the Yugoslavians experimented with new bullet designs to produce a round with a superior wounding profile, speed, and accuracy to the M43. Dr. Fackler also evaluated the M67 in the same manner that he evaluated the M43. The M67 projectile is shorter and flatter-based than the M43. This is mainly due to the deletion of the mild steel insert. This has the side effect of shifting the center of gravity rearward in comparison to the M43. This allows the projectile to destabilize nearly 17 cm (6.7 in) earlier in tissue. This causes a pair of large stretch cavities at a depth likely to cause effective wound trauma. When the temporary stretch cavity intersects with the skin at the exit area, a larger exit wound will result, which takes longer to heal. Additionally, when the stretch cavity intersects a stiff organ like the liver, it will cause damage to that organ.

However, without fragmentation, the wounding potential of M67 is mostly limited to the small permanent wound channel the bullet itself makes. While a fragmenting round (like the 5.56x45mm NATO) might cause massive tissue trauma and blood loss (and thus rapid incapacitation) on a lung or abdominal hit, the M67 has a greater chance of merely wounding the target. However, the 5.56x45 will only reliably fragment in close ranges below 125 metres (410 feet).

Many contemporary Russian-made 7.62x39 cartridges, such as those sold under the brand names Wolf Ammunition and Golden Tiger, feature a modified M67 bullet with an airspace cast into the nose or similar ballistic-enhancing tip design (e.g. 8m3) which improve fragmentation and/or tumbling tendencies.

Chinese steel core

7.62x39mm from China, Pakistan, and Russia.

Chinese military-issue ammunition in this caliber is M43 style with a mild steel core and a thin jacket of copper or brass. Contrary to common belief, the use of steel was a cost saving measure rather than one to increase penetration. Additionally, mild steel is not sufficiently hard to grant unusual armor penetrating capability. Despite this, Chinese ammunition (as well as all other M43 ammunition) is currently banned from importation in the US. U.S. federal law classifies the round as an armor-piercing handgun round. This classification is based on materials and bullet design rather than on empirical ability to penetrate armor.^[10]

Ballistics

The standard AK-47 or AKM fires a 7.62x39mm round with a muzzle velocity of 732 m/s (2,400 ft/s). Muzzle energy is 2,110 J (1,560 ft·lbf). Cartridge case length is 38.6 mm (1.52 in), and weight is 18.21 g (281.0 gr). Projectile weight is normally 8 g (120 gr). The AK-47 and AKM, with the 7.62x39mm cartridge, have a maximum effective range of around 350 m (1,150 ft).^[11]

Cartridge dimensions

The 7.62x39mm has 2.31 ml (35.6 grains H₂O) cartridge case capacity.

7.62x39mm maximum C.I.P. cartridge dimensions. All sizes in millimeters (mm).^[12]

Americans would define the shoulder angle at alpha/2 ≈ 16.4 degrees. The common rifling twist rate for this cartridge is240 mm (1 in 9.45 in), 4 grooves, Ø lands = 7.62 millimetres (0.300 in), Ø grooves = 7.92 millimetres (0.312 in), land width = 3.81 millimetres (0.150 in) and the primer type is small rifle. According to an American source some barrels can however have a non C.I.P. conform grooves diameter of 7.82 millimetres (0.308 in).^[13].

According to the official C.I.P. (Commission Internationale Permanente Pour L'Epreuve Des Armes A Feu Portative) guidelines the 7.62x39mm case can handle up to 355 MPa (51,488 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.

Other names for 7.62x39mm

On some occasions, this ammunition is referred to as 7.62 mm Soviet, 7.62 mm Warsaw Pact, or 7.62 mm ComBloc. It was also known in the United States as .30 Short Russian/ComBloc; the "Short" was to distinguish it from the older .30 Russian, which was the 7.62x54mmR.

Hunting and sport use

Since approximately 1990, the 7.62x39mm cartridge has seen some use in hunting arms in the US for hunting game up to the size of whitetail deer, as it is approximately as powerful as the .30-30 Winchester round, and has a similar ballistic profile.^[14] Large numbers of inexpensive imported semiautomatic rifles, like the SKS and AK-47 clones and variants, are available in this caliber.

In addition, several AR15 manufacturers such as Olympic Arms, Del-Ton Inc, and ModelOne Sales are producing 16" carbines and 20" to 24" rifle length firearms that can often get very good accuracy to about 1" groups at 100 yards.

Ruger produces the Mini-30 as a 7.62x39mm version of their popular Mini-14 rifle.

Remington Arms introduced its Compact Model 799 Mini Mauser bolt action rifle chambered in 7.62x39mm in 2006, describing the Mauser action as "sought after by today’s hunters and shooters."^[15] The Mauser action is a copy of the Gewehr 98 model rifle's action.

CZ-USA Sells the "micro length Mauser style" bolt action chambered in 7.62x39mm.^[16]

The low cost and high availability of military surplus ammunition makes this cartridge attractive for many civilian shooters, although for hunting large game, many people prefer the 154gr soft point, which is usually labeled under the Wolf brand.

See also

• List of rifle cartridges
• 7.62 mm caliber

References

External links

• Various photos of 7.62x39mm ammunition
• .30 Caliber cartridge article at Chuck Hawks