7.62x39mm

7.62x39mm

Caliber Condition - Living7.62×39: From Russia With Love

Few other calibers have such name recognition as the 7.62×39, 7.62×39 Soviet, or just 7.62. This Russian made cartridge has been used in conflicts the world over. From dense jungles to searing deserts the 7.62x39mm round has proved that it, along with its iconic platform, the AK-47, is capable well over seventy years after it was first adopted by the Russian military in 1944. The 7.62×39 stands as my personal favorite round for many reasons. It’s cheap, easy to find in bulk, and there’s something elegant about the efficient simplicity of the AK-47, a rifle that I’ve owned a number of variants over the years.

A Call For Arms

The origins of the AK-47’s main cartridge date back to July 15, 1943, arising out of a meeting of the Technical Council of the People’s Commissariat for Armaments (Техсовет Наркомата Вооружения). It was during this meeting that the Commissariat for Armaments decided what the requirements for the new caliber would be. They wanted a round that would be suitable for use in a number of different platforms, from select fire rifles, to carbines, and machine guns. The eventual final plan was to develop an intermediate cartridge much like what they had seen on the battlefields of World War II in German Sturmgewehr 44’s. This would mark a burgeoning trend in small arms design, moving away from full powered rifle cartridges to so-called “intermediate” cartridges. These calibers, like the 7.62x39mm, strike a balance between the long-range effectiveness of rounds such as the .30-06 and pistol caliber sub-machine guns. While “high power” rounds are effective for engaging targets at long distances, the controllability of such rounds becomes more of a problem in semi-auto and fully automatic rifles, especially with sustained fire. Conversely, sub-machine guns were effective at close range and able to lay down impressive rates of fire, but were poor for longer distance engagements. The general trend of small arms design during this time was to try to strike a balance between these two extremes and develop controllable rounds that could still deal with targets at longer distances. With the typical combat distances of between 150 to 300 meters being the practical effective target range for these new rounds. It was with these ideas in mind that the Commissariat tasked NM Elizarov (Н.М. Елизаров) and his assistants, PV Ryazanov (П.В. Рязанов), BV Semin (Б.В. Семин), and IT Melnikov (И.Т. Мельников) with the development of the new round.

Many Hands Make Light Work: The Many Designers of the 7.62×39

Fedor Tokarev
Fedor Tokarev was one of many designers who consulted with NM Elizarov and his team

The early development of the 7.62×39 saw the collaboration of a number of some of the most respected firearms designers of the time with the Commissariat’s team. NM Elizarov brought in Vladimir Grigoryevich Fyodorov, designer of the  Fedorov AvtomatFedor Tokarev, creator of the 7.62×25mm TokarevSergei Gavrilovich Simonov who would also design the SKS in 1943; and Georgy Shpagin, inventor of the PPSh-41 sub-machine gun. With this team of eight talented gunsmiths and designers roughly 314 different design ideas were created for the new round. From this batch, eight were selected as being worthy for practical trials and were tested.

For the actual testing and development of the new round the work was done at the Experimental Design Bureau Number 44 (Опытное конструкторское бюро) which would eventually become the scientific research institute Number 44 (NII-44) (нау́чно-иссле́довательский институ́т). Range trials for the now almost finalized 7.62x39mm were completed in December of 1943 and the round would be officially adopted in 1944. Upon adoption this early iteration of the 7.62×39 was given the GRAU Index number of 57-N-231.

The GRAU Index is classification of various arms, armaments, and equipment used by the Russian Military. GRAU stands for The Main Missile and Artillery Directorate of the Ministry of Defense of the Russian Federation or in Russian, Главное ракетно-артиллерийское управление МО РФ (ГРАУ), Glavnoye raketno-artilleriyskoye upravleniye MO RF (GRAU). The Index assigns a category, sub-category and specific model number to each design used by the military, with suffixes indicating different variants.

Early Variants of the 7.62×39

7.62x41 - 7.62x39mm prototype
7.62x41mm was the original dimensions of the cartridge while it was being developed. Image via The Firearms Blog

Despite official adoption in 1944 the 7.62x39mm still had some growing to do. GRAU officials still had lingering complaints about the round and the 57-N-231 version of the 7.62x39mm looked rather different from what we are used to seeing today. The first design of the 7.62×39 had a case length of 41mm, with this variant sometimes called “7.62×41”. However this was not the only difference from the modern design that we are used to seeing today. The early design also used a lead core bullet that only reached it maximum diameter at 13.01mm from the nose of the bullet. Furthermore the bullet also lacked a boat tail as part of its design. It was assumed by the designers that the addition of the boat tail would only affect accuracy at long ranges, when the round became subsonic, however this was incorrect. Once pilot production of the round began in march of 1944, and much more exhaustive testing and ballistics information was available, it seemed a slight redesign of the cartridge was in order.

First a boat tail was added as ballistics testing showed that even at close ranges, when the round was still super sonic, the boat tail improved the accuracy of the round. Because of the loss of mass due to the boat tail the overall length of the bullet’s ogive was increased to 26.8mm and the taper was extended, with the bullet now having its maximum diameter 15.95mm from the tip of the bullet. However because the bullet was now longer and the designers wanted to preserve the overall length of the cartridge the case dimensions were trimmed back. The formerly 41mm case was shortened to a length of 39mm, finalizing the dimensions of the round as 7.62x39mm.

bakelite magazines
The 7.62×39 would see a number of revisions before being finalized.

However the changes to the bullet did not stop there. The once lead core was changed to a low-carbon steel core wrapped in lead with a copper plated steel jacket. Finally the case used a berdan primer, common for European cartridges. This change to the bullet happened, not for additional fragmentation reasons, but for more mundane ones. The Soviet Military, like many militaries around the world wanted to save money. A large amount of industrial equipment was already in use producing materials for the 7.62x25mm Tokarev and it made more sense to the bean counters in the Soviet Military to utilize the same resources that were already up and running for another round. The bullet would be designated the 7.62 PS (76.2 ПС) with the “S” standing for “Surrogate” (суррогатированная). It’s possible that this came from an uncertainty as to whether or not the new design would be the final one to go into full-scale production. However the new design would finally win over its nay sayers in mid 1947 and the round entered into full-scale production. At this time the 7.62 PS designation remained however the name changed from “Surrogate” to “Steel” to denote the steel core, which made up half of the core’s volume. This final production design was given the index 57-N-231S and was fully accepted by the GRAU in to Soviet service. The 57-N-231S bullets are often referred to as the M43 variant, both terms refer to this steel and lead core bullet.

7.62×39 Continues to Evolve: Later Variants

While the first proper 7.62×39 utilized bimetallic, steel and copper, cases, refinements and improvements continued to be made to the cartridge. The early 1960’s saw the use of all steel lacquered cases. Initially these cases were given a special designation by GRAU and were called 57-N-231SL. However there was a push to simplify things and make the terminology less complicated. Shortly after the use of these lacquered steel cases started the 57-N-231 was changed to refer to all 7.62x39mm steel core rounds, no matter what cases they were using, lacquered or bimetallic.

Despite having designed a round that would go on to be one of the most ubiquitous the world over NM Elizarov was not done yet. In the 1950’s Elizarov’s team had moved to the NII-61 lab and were hard at work testing a new subsonic round for use with suppressors. For this new round Elizarov looked to the bullet design and made a number of changes. First was an increase in both length, to 33.62 mm, and weight, to 12.5 g. However this was not the only dimension to be increased in these new rounds. The maximum diameter was increased to 7.94mm up from the 7.62mm of other 7.62x39mm rounds. There was a method to this madness however. The new, larger, diameter was intended to better engage with the rifling in the barrel. Yet modifications to the bullet did not stop with these changes in dimensions. This subsonic variant of the 7.62x39mm also used an interesting design. The core was in two parts, the tip using tool steel, with the rear using lead. The resulting round had a velocity of between 285 to 300 meters per second. Once formally adopted the new subsonic 7.62x39mm variant was given an index number of 57-N-231U. The bullet that the new variant used was called 7.62 US, with the “US” standing for уменьшенной скоростью or “reduced speed”. When the subsonic 7.62x39mm round entered into service it was painted black on the tip with a green band underneath for ease of identification. The Russian troops would pair this round with the PBS-1 suppressor, which has recently been reproduced by Dead Air Armament as the Wolverine PBS-1.

Shown from left to right: 7.62x39 steel core, 57-N-231 standard AK military bullet 57-N-231P tracer, the tracer cup (open at the bottom and made from copper washed steel) and lead tip. Image via Wikipedia.
Shown from left to right: 7.62×39 steel core, 57-N-231 standard AK military bullet 57-N-231P tracer, the tracer cup (open at the bottom and made from copper washed steel) and lead tip. Image via Wikipedia.

Meanwhile the 1960’s saw further improvements to the 7.62x39mm from the arms designers of Yugoslavia. Despite having distanced themselves from the Soviets in 1948 the Yugoslavians still used Soviet arms designs and sought to improve upon the 7.62×39. A common issue that is noted with 7.62x39mm rounds is that it traverses a great deal of tissue, typically ten inches, before it begins to tumble unless it hits bone. While later designs such as the 5.45x39mm would solve this problem Yugoslavian designers found a different solution. By removing the mild steel insert of previous bullet designs they found that the round would tumble much sooner; by 6.7 inches. The removal of the mild steel insert shifted the center of the bullet’s gravity back, allowing for this increase in performance on target.

Shortly after 1989 the 7.62×39 saw more changes to its bullet design. The steel core was not only given more carbon but was heat-treated as well. This allowed for a 1.5x to 2x times increase in the penetration of the bullet. Despite these changes these “newer” PS bullets were not marked differently than their older, softer, counterparts, making the manufacturing date the only reliable way to determine the exact core composition.

During this same time period from the 1980’s into the 1990’s a new bullet was in development for the Russian Military. Designated as “BP” this new design replaced the core with tool steel, further increasing the penetration capability of the 7.62x39mm. In addition to this new composition of the core, the length of the bullet was increased to 27.4mm The new penetration capabilities were not only roughly over three times what the original 7.62x39mm was capable of but was also able to defeat the Russian 6B5 bullet proof vests. In 2002 the Russian Military officially adopted the round with the index of 7N23.

Finally the 7.62x39mm has two tracer variants in use by the Russian Military, the 57-N-231P and the 57-N-231PM1. These tracer rounds are identified by their green tips, using 116 grain bullets that burn from 50 meters from the muzzle to 850 meters out.

German Influence On The Design of the 7.62×39?

One long-standing controversy over the 7.62x39mm is how much the Germans influence its design.

On the one hand there is some interesting evidence to suggest that the design was influenced by German small arms at the time. In 1940 Hitler brought in a number of Soviet engineers to Germany to tour a number of armament plants including the Gustav Genschow and Co. (GECO) plant. C. J. Chivers speculated that it is possible that the Russian engineers were able to see the Vollmer M35 and the cartridges that they fired. Given that these prototype rounds for the Vollmer M35 and the 7.62×39 share some similarities this is a possible explanation. However other authors argue against this conclusion. Anthony Williams contends that the Soviets’ rounds were far too different in construction that it was more likely to be an original idea of NM Elizarov and his team. At the end of the day the evidence is, at best, inconclusive and does not definitively show how much, if at all, the German small arms program influenced the design process of the 7.62×39.

Dispelling Myths About the 762x39mm

One of the great myths of the 7.62×39 and the AK-47 is that they are somehow inherently inaccurate when compared to other rounds. This is simply not the case. As any owner of a well made AK-47 will attest, an AK is perfectly able to deliver acceptable accuracy well out to 200 to 300 meters and beyond. Below we see James from the Firearms Blog tackling this myth. Showing both an AR-15 and an AK-47 delivering the same sized groups at 100 yards using steel cased ammo.

Another pseudo myth about the AK-47 is its reliability. While many overestimate how reliable the AK-47 is, the AK is a tool like any other and despite a very reliable track record, it can malfunction. The design of the cartridge does help to keep the gun running however. Unlike many straight walled cases, the 7.62×39 uses a taper in the case wall. This taper is what gives the AK-47 magazines their distinct look and curve, however it does more. The taper causes the walls of the case to have limited contact with the chamber until it is fully seated in place. This also helps in the reverse during extraction, again, causing less friction as the round is extracted from the chamber.

Reloading and Factory Ammo

The PDX Defender in 7.62x39mm makes this round even more viable for home defense.
The PDX Defender in 7.62x39mm makes this round even more viable for home defense.

Factory ammo for the 7.62x39mm is plentiful, easy to find at just about any gun or sporting goods store, and often inexpensive for steel cased rounds. While many companies make steel cased ammo for the 7.62×39 such as TulAmmo, Hornady and others, the most common steel cased ammo is Wolf. While no one expects extreme accuracy out of inexpensive AK-47’s higher end AK-47’s and other platforms using the 7.62x39mm have options as well. A number of manufacturers make brass cased 7.62x39mm including Federal and Lapua Ammunition. These rounds deliver greater accuracy and in the case of Federals offerings are intended for hunting. While most don’t think of the 7.62x39mm as anything other than a plinking round that might be pressed into home defense for those who, like myself, like the AK platform better than the AR, The Firearms Blog shows us that it is certainly capable of more than most people think. If you are looking to use 7.62x39mm as a home defense round I’d take a look at Federal’s offerings as well as the Winchester Defender line. Both are hollow point rounds that are designed to higher standards than your typical steel cased range ammo.

Reloaders of 7.62x39mm are few and far between given how easy the round is to buy and that many factory offerings are exclusively steel cased ammo, making reloading difficult. However brass, dies, and bullets are all available for the 7.62×39. So reloading the venerable round is far from impossible.

While researching for this article I came across an old Speer Reloading manual from 1988. It notes a bit of an oddity about  the 7.62x39mm of the time. During that time no US Manufacturers were producing 7.62x39mm ammo and what was being imported used the standard .311 bullet diameter. However in the case of the Ruger Mini-30 up until about 1993 the rifle used a .308 bore diameter with a very long and tapered throat to accommodate the larger .311 diameter bullets. The reloading manual recommends using .308 diameter bullets in the 7.62×39 as at that time .310 to .312 diameter bullets were almost impossible to find in the lighter sizes that the 7.62×39 required. Hence Ruger opted for a .308 bore diameter in their early Mini-30’s.

The Speer Number 11 Reloading Manual from 1988 notes the oddities of the Ruger Mini-30 and the scarcity of light .311 diameter bullets.
The Speer Number 11 Reloading Manual from 1988 notes the oddities of the Ruger Mini-30 and the scarcity of light .311 diameter bullets.
Load data for 7.62x39mm from 1988, note the use of .308 diameter bullets
Load data for 7.62x39mm from 1988, note the use of .308 diameter bullets

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Loading data for the 7.62x39mm is not terribly difficult to find, despite not being as frequently requested as other calibers. My 2007 Nosler #6 Reloading Manual omits the 7.62x39mm, a major oversight in my opinion. However with the internet reloading data is easier to find than ever and Hodgdon and Nosler keep up to date reloading information for the 7.62x39mm on their websites.

Chambered Firearms

The 7.62x39mm finds its most common home in the magazines of the AK-47 and the many copies, reproductions, and variants such as Saigas, WASR-10’s, and more. The SKS also uses 7.62×39 and is an easy to find and often less expensive alternative to an AK-47 clone. For those of you who are looking for a bit of Cold War firepower in your AR-15, both complete AR-15’s and AR-15 7.62x39mm uppers are available from a number of manufactures. SIG Sauer was making their SIG516 rifle in 7.62×39 however it appears to be discontinued along with the SIG 556xi Russian.  For those of you who are interested in a bolt-action 7.62×39 the CZ 527 Carbine might be a noteworthy option for you as well. If you are looking to shoot the 7.62×39 you will be hard pressed to not find something that will shoot it.

Billions of Rounds

Teaching to shootThe 7.62x39mm continues to be one of the most prolific calibers the world over and we salute it. It’s a fun to shoot, proven, and effective round that will most likely be popular for decades to come, despite having be supplanted in part by its younger brother the 5.45x39mm. However this caliber has certainly made its mark within the world of small arms design and hopefully will continue to see improvements and tweaks to keep it a relevant and competitive caliber.

  • Rafael Breban

    Great article.

    • Thank you, I put a bunch of time and research into putting it together.

  • Adam Byrnes

    Very cool site.

    • Thank you very much, I’ve put this together because of my love of firearms.