7.62×39mm

The 7.62×39mm (aka 7.62 Soviet or formerly .30 Russian Short)[5] round is a rimless bottlenecked intermediate cartridge of Soviet origin that was designed during World War II. Due to the worldwide proliferation of the Soviet SKS and AK-47 pattern rifles, as well as RPD and RPK light machine guns, the cartridge is used by both militaries and civilians alike.

7.62×39mm
Lateral view of a steel-cased 7.62×39mm FMJ cartridge.
TypeRifle
Place of originSoviet Union
Service history
In service1944–present
Used bySoviet Union, former Warsaw Pact, People's Republic of China, Egypt, Cambodia, North Korea, Vietnam, Cuba, Finland, Venezuela, many others
Production history
Designed1943
Produced1944–present
Specifications
Case typeRimless, bottleneck
Bullet diameter7.85-7.9 mm (0.309-0.311") SAAMI[1] 7.92 mm (0.312") CIP[2]
Neck diameter8.60 mm (0.339 in)
Shoulder diameter10.07 mm (0.396 in)
Base diameter11.35 mm (0.447 in)
Rim diameter11.35 mm (0.447 in)
Rim thickness1.50 mm (0.059 in)
Case length38.70 mm (1.524 in)
Overall length56.00 mm (2.205 in)
Case capacity2.31 cm3 (35.6 gr H2O)
Rifling twist240 mm (1 in 9.45 in)
Primer typeBoxer Large Rifle (brass)
Berdan (steel case)
Maximum pressure (C.I.P.)355.0 MPa (51,490 psi)
Maximum pressure (SAAMI)310.3 MPa (45,010 psi)
FillingSSNF 50 powder
Filling weight1.605 – 1.63 g
Ballistic performance
Bullet mass/type Velocity Energy
7.9 g (122 gr) 57N231 FMJ 730.3 m/s (2,396 ft/s) 2,108 J (1,555 ft⋅lbf)
10.0 g (154 gr) SP 641.3 m/s (2,104 ft/s) 2,056 J (1,516 ft⋅lbf)
8.0 g (123 gr) FMJ 738.0 m/s (2,421 ft/s) 2,179 J (1,607 ft⋅lbf)
Test barrel length: 415 mm (16.3 in.)
Source(s): Wolf Ammo[3] Sellier & Bellot[4]

Shortly after World War II, the AK-47 was designed, later becoming the world's most widespread military-pattern rifle. The cartridge remained the Soviet standard until the 1970s. It was largely replaced in Soviet service by the 5.45×39mm cartridge, which was introduced with the new AK-74 rifle, and continues in service with the modernized current-issue Russian Armed Forces AK-74M service rifle, as well as the AK-12 rifle. In the 21st century the 7.62×39mm remains a common service rifle chambering, including for newly developed rifles like the AK-15.

History
Steel-cased 7.62×39mm FMJ cartridge.
Fourth from left, 7.62×39mm shown alongside other cartridges

On July 15, 1943, the Technical Council of the People's Commissariat for Armaments (Russian: Техсовет Наркомата Вооружения) met to discuss the introduction of a Soviet intermediate cartridge. The Soviet planners also decided at this meeting that their new cartridge be used in a whole range of infantry weapons, including a semi-automatic carbine, a selective fire rifle, and a light machine gun. The job of designing the Soviet intermediate cartridge was assigned to a committee led by chief designer NM Elizarov (Н.М. Елизаров), assisted by PV Ryazanov (П.В. Рязанов), BV Semin (Б.В. Семин) and IT Melnikov (И.Т. Мельников). Elizarov collaborated closely with some leading weapons designers, including Fedorov, Tokarev, Simonov, and Shpagin. About 314 cartridge designs were considered theoretically, before narrowing the selection down to 8 models that were physically constructed and tested.[6] Most of the development work on the new cartridge took place at OKB-44, which was soon thereafter renamed as NII-44, and which in 1949 was merged with NII-61, itself merged with TsNIITochmash in 1966.[7]

A first variant of the new cartridge was officially adopted for service after completing range trials in December 1943; it was given the GRAU index 57-N-231. This cartridge actually had a case length of 41 mm, so it is sometimes referred to as the 7.62×41. The bullet it contained was 22.8 mm long and had a core made entirely of lead. This bullet has a somewhat stubbier appearance than later 7.62×39 bullets, with its maximal radius being attained after only 13.01 mm from its tip, and it was lacking a boat tail. After some further refinements, a pilot production series of this cartridge began in March 1944.[7]

After more detailed testing results became available, starting in 1947 the cartridge was tweaked by The Ulyanovsk Machine Building Plant in order to improve its accuracy and penetration. Initially, the boat tail had been omitted because the Soviet designers had assumed (incorrectly) that it would only make a difference at long ranges, when the bullet became subsonic, and the accuracy of the intermediate cartridge at these ranges was considered inconsequential. However, further testing showed that the boat tail improved accuracy even at shorter ranges, where the bullet was still supersonic. In order to maintain the overall mass of the bullet, after adding the boat tail, the ogival head section of the bullet was lengthened as well, making the bullet more streamlined overall. The maximum radius was now attained at some 15.95 mm from the tip and the overall length of the bullet increased to 26.8 mm. In order to preserve the total length of the cartridge, the case sleeve was shortened to 38.7 mm (and by rounding it is customarily referred to as 7.62×39.) Additionally, the new bullet had a core made of lead wrapped in low-carbon steel . The use of low-carbon (mild) steel was guided mostly by the desire to reuse some industrial equipment that was manufacturing the 7.62×25mm Tokarev cartridge rather than by bullet fragmentation considerations. This bullet was given the acronym "7.62 PS" (76.2 ПС). The "S" initially stood for "surrogate" (суррогатированная, surrogatirovannaya), but later the letter was taken to refer to the steel component (стальной, stal'noy) of the core, which accounted for about 50% of the core volume. The 7.62×39 cartridge equipped with the PS bullet finally overcame all objections of the GAU in mid-1947, when it was ordered into series production, and given the index 57-N-231S.[7] Field tests of the round & new prototype AK-47 were carried out at the NIPSVO from December 16, 1947 to January 11, 1948.

The design that was ultimately selected by the Soviets has more dimensional similarities to the GECO cartridge used in the Vollmer M35 than with the Polte round used by the later German Sturmgewehr. Some authors, including C. J. Chivers, have speculated that the Soviets may have had access to the works of GECO and Vollmer during 1940, when Hitler allowed a large number of Soviet engineers to tour various German armament factories.[8] Anthony G. Williams, however, argues that the Soviet M43 round was so different that it was possible to dismiss the idea that it was a copy of any German round in existence at the time.[9]

The 57-N-231S cartridge used a "bimetallic" (steel and copper) case. In the early 1960s, a "lacquered" steel case was introduced, and the new cartridge was initially given the designation 57-N-231SL. In an effort to simplify terminology, sometime thereafter the 57-N-231 designation was recycled to denote all steel-core 7.62×39 Soviet ammunition, irrespective of case build.[7]

In the mid 1950s, Elizarov's team, now working at NII-61, developed a special subsonic bullet for the 7.62×39 cartridge. It was adopted for service in 1962, and given the army designation "7.62 US" (US stood for уменьшенной скоростью, meaning "reduced speed") and the GRAU index 57-N-231U. The subsonic bullet was considerably longer (33.62 mm) and heavier (12.5 g) than the PS bullet, and also had a different, non-layered core structure. The core of its head section was entirely made of tool steel, followed by another section entirely made of lead. The subsonic bullet also has a larger maximum diameter of 7.94 mm compared to all other 7.62×39 bullets that peak at 7.91 mm diameter; the larger diameter of the lead-core section was intended to provide a tighter fit to the barrel by better engaging the rifling grooves. The 7.62 subsonic ammo was intended to be fired from AK-47-type rifles equipped with the PBS-1 silencer, and developed a muzzle velocity of about 285–300 m/s. For recognition, this ammo typically has the bullet tips painted black with green band underneath.[7]

After 1989, the regular (PS) Russian bullets started to be manufactured with a steel core with a higher carbon concentration and subjected to heat treatment. This change improved their penetration by 1.5–2 times. It is not possible to externally distinguish these bullets from the earlier, softer PS ones except by year of fabrication. At about the same time, tool steel was adopted for a normal velocity 7.62×39 bullet. Called BP, this bullet was developed in the 1980s and 1990s. It was officially adopted for Russian service in 2002 under the service name "7.62 BP", and with the GRAU designation 7N23. The BP bullet is claimed to achieve over three times the penetration of the PS bullet; it can defeat the Russian bullet-proof vest with designation 6B5 at distances below 250 meters. The BP cartridge has the tip of its bullet painted black. The BP bullet itself is slightly longer (27.4 mm) compared to the PS bullet, but has the same mass of 7.9 grams.[7]

At the same 1943 meeting that decided the development new cartridge, the Soviet planners decided that a whole range of new small arms should use it, including a semi-automatic carbine, a fully automatic rifle, and a light machine gun. Design contests for these new weapons began in earnest in 1944.[6]

Variants

M43
From left to right: 7.62×54mmR, 7.62×39mm and 7.62×25mm Tokarev.
7.62×39mm bullet wound on an American soldier from the Vietnam War.

The original Soviet M43 bullets are 123 grain 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 consisted 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. The ballistic coefficient (G7 BC) of the M1943 pattern full metal jacket boat bullet is 0.138.[10]

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 26 cm (10 in) of tissue.[11] This greatly reduces the potential wounding effectiveness of the projectile against humans.

M67

In the 1960s Yugoslavia experimented with new bullet designs to produce a round with a superior wounding profile, speed, and accuracy to 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.[11] 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, the wounding potential of M67 is mostly limited to the small permanent wound channel the bullet itself makes, especially when the bullet yaws (tumbles).[11]

Commercial ammunition

Commercial Russian-made 7.62×39mm ammunition, such as those sold under the Wolf Ammunition brand name, are also available in full metal jacket (FMJ), soft-point (SP) and hollow-point (HP) variety.[3] The SP bullets offer improved expansion.

Type 56: Chinese Mild Steel Core

Chinese (Type 56) military ammunition (developed in 1956) is a M43 style cartridge with a mild steel core (MSC) and a thin copper or brass jacket. In 1956, the Chinese developed their own 7.62x39mm assault rifle. It is a variant of the Soviet-designed AK-47(specifically Type 3 and AKM) assault rifles. Production started in 1956 at State Factory 66 but was eventually handed over to Norinco, who continues to manufacture the rifle primarily for export. Norinco developed and produced a 7.62x39mm ammunition for the new Chinese Type 56 7.62x39mm rifle. The Chinese ammunition (as well as all other M43 ammunition) is currently banned from importation in the U.S. because 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.[12]

Cartridge dimensions

The 7.62×39mm has 2.31 ml (35.6 grains H2O) cartridge case capacity.

7.62×39mm maximum C.I.P. cartridge dimensions. All sizes in millimeters (mm).[13]

Americans would define the shoulder angle at alpha/2 ≈ 16.4 degrees. The common rifling twist rate for this cartridge is 240 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 usually large rifle, with the exception of commercial Remington/UMC brass using small rifle primers.

According to the official C.I.P. (French: Commission Internationale Permanente pour l'Epreuve des Armes à Feu Portatives) rulings the 7.62×39mm can handle up to 355.00 MPa (51,488 psi) Pmax 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. This means that 7.62×39mm chambered arms in C.I.P. regulated countries are currently (2015) proof tested at 444.40 MPa (64,455 psi) PE piezo pressure.[13]

The SAAMI Maximum Average Pressure (MAP) for this cartridge is 45,000 psi (310.26 MPa) piezo pressure.[14]

Basic specifications of 21st century Russian service loads
From left to right: steel core, 57-N-231 standard AK military bullet with steel core, green tipped 57-N-231P tracer, the tracer cup (open at the bottom, made from copper washed steel) and lead tip. The jackets of both bullets are copper washed steel.

The 7.62×39mm rounds in use with the Armed Forces of the Russian Federation are designed for AKM assault rifles and AK-derived light machine guns. As per 2003 there were several variants of 7.62×39mm produced for various purposes. All use clad metal as case material.

The 57-N-231 conventional steel-core bullet is designed to engage personnel and weapon systems. The bullet has a steel core and has a ballistic coefficient (G1 BC) of approximately 0.304 and (G7 BC) of approximately 0.152. The tip has no distinguishing colour. It can penetrate a 6 mm (0.2 in) thick St3 steel plate at 300 m (328 yd) and 6Zh85T body armour at 30 m (33 yd).

The 7N23 armour-piercing bullet, introduced in 2002, has a 3.6 g (55.6 gr) sharp-pointed steel penetrator made of steel U12A and retains the soft lead plug in the nose for jacket discarding. The bullet has a black tip.[15][16]

The 57-N-231P is a tracer round designed for fire adjustment and target designation. The bullet has a green tip and the tracer burns for 800 m (875 yd). The 57-T-231PM1 is an improved tracer round which initiates at 50 m (55 yd) from the muzzle and burns for 850 m (930 yd).

Cartridge designation[17][18] 57-N-231 57-N-231P (tracer) 57-T-231PM1 (tracer)
Cartridge weight 16.3 g (252 gr) 16.1 g (248 gr) 16.05 g (248 gr)
Bullet weight 7.9 g (121.9 gr) 7.57 g (116.8 gr) 7.55 g (116.5 gr)
Muzzle velocity 718 m/s (2,356 ft/s) 718 m/s (2,356 ft/s) 718 m/s (2,356 ft/s)
Muzzle energy 2,036 J (1,502 ft⋅lbf) 1,951 J (1,439 ft⋅lbf) 1,946 J (1,435 ft⋅lbf)
Accuracy of fire
at 300 m (328 yd) R50[A]		 75 mm (3.0 in) 140 mm (5.5 in) 140 mm (5.5 in)

A 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).
B Military 7.62×39mm ammunition is purportedly tested to function well in temperatures ranging from −50 to 50 °C (−58 to 122 °F) cementing its usefulness in cold polar or hot desert conditions.

Hunting and sport use

Since approximately 1990, the 7.62×39mm cartridge has seen some use in hunting arms in the U.S. for hunting game up to the size of whitetail deer, as it is somewhat less powerful than the .30-30 Winchester round, and has a similar ballistic profile.[19] Large numbers of imported semiautomatic rifles, such as the SKS and AK-47 clones and variants, are available in this caliber.

In addition, several AR-15 manufacturers have produced the 7.62x39mm option. Some current and past companies include AR-Stoner, Armalite, Colt, Rock River Arms, Olympic Arms, DPMS, Del-Ton Inc, and ModelOne Sales. Custom builds and conversion kits are available as well. Wide availability and low cost ammo with a wide variety of manufacturers make it a much lower cost of operation compared to other 5.56x45mm alternatives. Conversions include a new bolt, firing pin, extractor, barrel, and magazine.[20]

Ruger produces the Ruger Mini Thirty as a 7.62×39mm version of its popular Ruger Mini-14 rifle; often incorrectly called Mini-30.[21][22] In 2017 Ruger began production of a model of the American Rifle in 7.62x39.[23] It once had its bolt-action M77 Mark II available in this caliber.[24]

For a time, Remington Arms advertised the Compact Model 799 Mini Mauser bolt-action rifle chambered in 7.62×39mm in 2006, describing the Mauser action as "sought after by today’s hunters and shooters."[25] The Mauser action is a copy of the Gewehr 98 model rifle's action.

CZ-USA sells the CZ 527 Carbine, a "micro length Mauser style" bolt-action rifle chambered in 7.62×39mm and .223 Remington.[26]

Savage Arms has introduced (around 2010–2011) their own bolt-action rifle in 7.62×39mm caliber - Model: 10 FCM Scout.[27]

Both the SIG Sauer SIG516 Russian and the SIG 556R are chambered in 7.62×39mm.

Romania produces a 7.62x39mm WASR-10 Modern sporting rifle in an AK style semi-automatic rifle designed for the sporting market.

Howa introduced in 2016 a bolt-action rifle chambered in 7.62x39mm that uses their long-standing Howa M1500 barreled action. The model is called the Howa Mini-Action and is specifically design for shorter intermediate cartridges.[28]

The lower cost and high availability of military surplus ammunition makes this cartridge attractive for many civilian hunters, plinkers, target and metallic silhouette shooters.

  • Wound Profiles of Russian small-arms ammunition compiled by Dr. Martin Fackler on behalf of the U.S. military.
  • Wound ballistics profile of 7.62×39mm.
  • 7.62×39mm ammunition and snap cap.
  • SKS rifle with a 10-round stripper clip of 7.62×39mm ammunition.
  • Magazine for a Finnish RK-62 loaded with 7.62×39mm ammunition.
  • "Bakelite" polymer AK magazines loaded with 7.62×39mm ammunition.
  • Three magazines and a stripper clip loaded with 7.62×39mm ammunition.
  • Loading 7.62×39mm ammunition into an AK magazine.
  • An AK magazine loaded with 7.62×39mm ammunition.
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gollark: https://osmarks.tk/crash/
gollark: One day I'll make that EnhancedFS API with actual sanity.
gollark: "Worked".
gollark: Well, the garbage collector does it apparently.

See also

References
  1. "SAAMI spec sheet (7.62x39mm on page 53)" (PDF). Archived from the original (PDF) on 2019-01-25. Retrieved 2019-01-24.
  2. "CIP spec sheet for 7.62x39mm" (PDF). Archived (PDF) from the original on 2018-07-14. Retrieved 2019-01-24.
  3. "Steel Cased Ammo - Wolf Performance Ammunition". Archived from the original on 6 November 2016. Retrieved 30 January 2016.
  4. "Product detail 7,62×39 — Sellier & Bellot". Archived from the original on 5 December 2015. Retrieved 30 January 2016.
  5. Lawrence, Erik (2015). Practical Guide to the Operational Use of the RPD Machine Gun. p. 17. ISBN 978-1-941998-35-9.
  6. Monetchikov, Sergei (2005). История русского автомата [The History of Russian Assault Rifle] (in Russian). St. Petersburg: Military Historical Museum of Artillery, Engineers and Signal Corps. pp. 24–25. ISBN 978-5-98655-006-0.
  7. "Патрон - основа оружия. Глава третья. Из истории автоматного 7,62-мм патрона образца 1943 г. (7,62х39)", Оружие 2005/9, pp. 21-44
  8. C. J. Chivers (2010). The Gun. Simon & Schuster. pp. 166–167. ISBN 978-1-4391-9653-3. Retrieved 2016-11-02.
  9. "Assault Rifles and Their Ammunition: History and Prospects". Archived from the original on 17 July 2015.
  10. "The 6.5×40 Cartridge: Longer Reach for the M4 & M16". Small Arms Defense Journal. Archived from the original on 2015-01-23. Retrieved 2015-01-14.
  11. Military rifle bullet wound patterns - by Martin L. Fackler. From: http://www.uthr.org/SpecialReports/Military_rifle_bullet_wound_patterns.htm Archived 2011-09-10 at the Wayback Machine. Retrieved on November 9, 2011
  12. "US Code: Title 18, Part 1, Chapter 44, § 921". Archived from the original on 2 January 2016.
  13. "C.I.P. TDCC sheet 7,62 x 39" (PDF). Archived (PDF) from the original on 2015-01-22. Retrieved 2015-01-22.
  14. ANSI/SAAMI Velocity & Pressure Data: Centerfire Rifle Archived 2013-07-15 at WebCite
  15. "патрон 7,62х39 7н23". patronen.su. Archived from the original on 2019-02-12. Retrieved 2019-02-11.
  16. Соловцов Е.В. Российские боеприпасы Промежуточные патроны (PDF) (in Russian). Archived (PDF) from the original on 2019-02-02. Retrieved 2019-02-11.
  17. Russian 7.62x34mm Rounds for Rifles and Machine Guns, Land Forces Weapons Export Catalog, page 85 Archived 2011-12-16 at the Wayback Machine
  18. "warfare.be". warfare.be. Archived from the original on 2015-11-07. Retrieved 2013-01-21.
  19. Warner, Ken (1989). Gun Digest 1990: 44th Edition. DBI Books. p. 147. ISBN 978-0-87349-038-2. Trajectories are identical according to Remington
  20. Adelmann, Steve (2014-09-26). "AR Accuracy with 7.62x39 mm". www.shootingillustrated.com. Archived from the original on 2016-09-16. Retrieved 2017-04-07.
  21. Warner, Ken (1989). Gun Digest 1990: 44th Edition. DBI Books. p. 147. ISBN 978-0-87349-038-2. Trajectories are identical according to Remington
  22. https://ruger.com/products/miniThirty/models.html%20Mini-Thirty
  23. "Ruger News". www.ruger.com. Archived from the original on 2017-10-19. Retrieved 2017-10-18.
  24. "Ruger News". www.ruger.com. Archived from the original on 2017-10-19. Retrieved 2017-10-18.
  25. "Mauser Action Rifles Now in Remington Country". Archived from the original on 2010-07-01. Retrieved 2010-08-28.
  26. Rand. "CZ-USA". Archived from the original on 2010-09-01. Retrieved 2010-08-28.
  27. "Savage Arms". Archived from the original on 2011-05-03. Retrieved 2011-05-23.
  28. "Test:Howa 1500 Mini Bolt Highlander 7.62x39 mm Rifle by B. Gil Horman - Friday, January 13, 2017". Archived from the original on April 9, 2017. Retrieved April 8, 2017.

Further reading
  • (in Russian) Юрий Пономарёв "БИОГРАФИЯ ПАТРОНА", КАЛАШНИКОВ. ОРУЖИЕ, БОЕПРИПАСЫ, СНАРЯЖЕНИЕ 2004/8, pp. 10–16
  • (in Russian) К. Соловьев, “"Попурри" для символов 7,62” (factory identification guide), Ружье. Оружие и амуниция 1996/1, pp. 28–33
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