Modern Intermediate Calibers 002: The Soviet 7.62x39mm

7.62x39 and two of its derivatives. Left to right: Commercial FMJ, Yugoslavian M67, 5.6x39mm/.220 Russian, 6.5x38 Grendel.

7.62x39 and two of its derivatives. Left to right: Commercial FMJ, Yugoslavian M67, 5.6x39mm/.220 Russian, 6.5x38 Grendel.

Perhaps the oldest rival of the 5.56mm round is its older brother in the intermediate cartridge world, the 7.62x39mm round developed by the Soviets in the late 1940s from their earlier 7.62×41 M43 cartridge. The 7.62x39mm, despite its age, has maintained a very uniform ballistic profile. The original 8 gram (123gr) boattailed steel-cored bullet, also called “M43” like its predecessor, has become the representative load for the whole caliber, even while lead-cored flat-based incarnations like the Yugoslavian M67 ball round have proliferated.

Therefore it’s this M43 “PS” (“steel ball”) ball round that we’ll consider for our ballistic series. It is the most relevant 7.62x39mm round from a military perspective, and it’s ballistically similar to the vast majority of other loads for the caliber.
NW8aYax BIDjKyp CVuh2Cb RtHIQsg

The 7.62x39mm is, thanks to its fairly heavy bullet by intermediate caliber standards, one of the heaviest rounds we’ll be taking a look at, with weights ranging from 16.3 grams (252 grains) for a steel cased cartridge to 17.2 grams (265 grains) for the brass-cased M67 Yugoslavian round.

Note: All ballistic calculations are done with JBM’s Trajectory calculator, using the ballistic coefficient appropriate to the projectile being modeled. In this case, the calculations were done assuming an AK as the parent rifle. Also, keep in mind that there is no single true velocity for a given round; velocity can vary due to a large number of factors, including ambient temperature and chamber dimensions. Instead, I try to use nominal velocity figures that are representative of the capability of the round in question.



Nathaniel F

Nathaniel is a history enthusiast and firearms hobbyist whose primary interest lies in military small arms technological developments beginning with the smokeless powder era. In addition to contributing to The Firearm Blog, he runs 196,800 Revolutions Per Minute, a blog devoted to modern small arms design and theory. He can be reached via email at nathaniel.f@staff.thefirearmblog.com.


Advertisement

  • Anonymoose

    Needs moar SKS.

  • Major Tom

    So what does that make 8mm Kurz? (7.92×33) Ancient intermediate calibers?

    • zardoz711

      Yes, it is the grandfather, the patriarch, the paterfamilias of intermediate cartridges.

      • Not to downplay its significance, but I would argue the intermediate caliber is far older: http://www.thefirearmblog.com/blog/2016/01/31/short-essay-intermediate-rounds-1860-1943/

        • Kivaari

          All the 6.5mm rounds of the 1890s forward. The 6mm Lee Navy, 7.5mm Swiss experimental, pre-WW2 Soviet 5.5mm, 7.35mm, .25-.30-.32 Remington (rimless) etc.

          • I’d argue the intermediate cartridge goes all the way back to 1860, actually, with the Henry and Spencer. Possibly even further back than that.

          • Kivaari

            I’d agree. like the smaller Swiss and Italian rounds. Smaller cases with modest powder charges. Should we consider all the black powder rounds with 30-60 grains of powder, compared to the 70-90 grains so common of the era? Like the .45-55 Carbine load having a .45-70 case, a 405 gr. bullet, fiber wad and the small charge?

          • Setting an exact definition has always been a problem for intermediates. I rather like focusing instead on whether a given weapon seems to fit into a certain role or not. Does the Trapdoor Carbine? Not exactly, but the Henry and Spencer do pretty much fit in with the idea of a lighter, more rapid-firing weapon.

            But then, if you want to consider the Italian and Japanese reduced-power 7.62 loads to be intermediate rounds, then there doesn’t seem to be an issue considering the .45-55 to be one, either.

  • Rousso

    To get the real Russian extended ballistic tables for AK, search in Google:
    Таблицы стрельбы по наземным целям из стрелкового оружия калибров 5,45 и 7,62 мм

    Scroll down and click on the link in the bottom of the page to download

    • c4v3man

      Either:
      A. Really insightful post helping link to untranslated content from the nation that created the caliber.
      B. An elaborate ploy to trick someone into viewing a Rick Roll/Hilariously Offensive Video.

      • Bland Samurai

        You’d know if you read Russian…

      • Max Popenker
        • Rousso

          This is it

      • Max Popenker
      • Rousso

        “Таблицы стрельбы по наземным целям из стрелкового оружия” translates as “ballistic tables for the small arms”. This is a manual used by the Russians. It contains tables for AK, SVD and other Soviet rifles. There are about 80 tables on 260 pages.

        www_scribd_com/document/319272967/AK47-AK74-BallisticTables

        Replace underscores with dots, paste the link and download. But you will have to run the OCR scan on this PDF to make it searcheable in order to be able to use Google Translate to read it. I can’t do that, since I don’t have the needed soft. Or else, the original file that I referenced earlier is a DjVu format document, it requires WinDjView to read it and CuneiDjVu for the OCR scan, both programs are free.

        The original DjVu looks the same as PDF, I uploaded it here:
        www_docspal_com/viewer?id=yetsrqdq-10389009

        But it can’t be downloaded from this link.

        In these tables there are all the trajectories for all the sight settings, statistics for the amount of rounds needed to be fired to hit various targets for average and advanced shooters, ballistic formulas, etc.

  • guest

    How on God’s green earth is a cartridge designed in 1943 being considered “modern”?
    I am in no way arguing against its modern use (and continued use) despite its age, and by all means it is still very useful and potent in every way, but the choice of words like “modern” should imply the exact meaning of the word.
    Since USSR/Russia along with many other nations has a very long service life of calibres (just look at 7,62x54r and 12,7×99 or 12,7×108) it stands to reason that at the very least the term “modern” would be used with something that is at least the latest fielded cartridge – like 5.56, 5,45, 9×39 etc.

    As for the bogus comparison of 5.56 vs 7,62×39 keep in mind that the “second generation” of intermediate cartridges were supposed to not just continue the rational minimalization of overall weight as per the *real* tasks that infantry had to solve (short to intermediate range, no more “every man a marksman out to 1km” nonsense, full auto fire minus the huge recoil, carry more ammo contra full sized rifle cartridges etc), but also solve the inherent flaws of the first intermediate cartridges like less bullet drop and greater penetration – to which 5,45 got an added bonus from the very start by being specifically designed with a bullet that would tumle on impact and cause more internal damage, thus “reverting” performance wise back to the similar lethality of the full sized rifle calibres that did the same thing by bullet mass and velocity, minus the added weight.

    So please, stop pulling random words and arguments out of thin air. I love TFB but small things – or very big issues, depends on how it’s viewed – ruin a great deal of artilcles, along the line of the “submachine gun” AKS-74U etc.

    • 7.62x51mm NATO was designed over the same time period, do you consider it to not be modern?

      Also, 5.56mm was designed just a few years later, is it not modern as well?

      Whether a cartridge performs well ballistically or not is not a criterion I am using for this series. If it were, I’d basically cover just 5.45×39 and 6.5 Grendel and nothing else. What is actually important is how these rounds have influenced the thinking on intermediate cartridges, especially the potential next generation that has yet to be designed. 7.62x39mm has absolutely been influential, and led in some way to three of the other cartridges in upcoming posts.

      • guest

        I do not not understand wether you understand anything I have written:
        “modern” is a very loose term as I explained, if applied to actually issued and used military cartridges. As I said “modern” can in that sense apply to the “latest” cartridge, which may be either 0 years or 100+ years old, being the last “heir” of whatever came before it. Hence calling a cartridge that is older than the latest issued and used cartridge of USSR/Russia “modern” can not apply to 7,62×39. There may be modern *modification* of the cartridge as in newer bullet types, better powder, better case material etc, so those can be called “modern”, but that can not possibly apply to the cartridge as a whole unless you are speaking of a radical change of dimensions.

        And as a side-tracking to the main argument, to your “especially the potential next generation that has yet to be designed.” then I will also argue against this, as there is literally no cartridge that can at this point seriously revolutionize small arms (even caseless/telescopic ammo), and the real next step is no a cartridge but a weapon type which will use different means of accelerating projectiles than archaic gun powder.

        • 7.62x39mm is still in use with some nations, for example Finland.

          Your argument is irrelevant and pedantic in relation to the post itself.

    • Travis Kay

      When we speak of modern here, I’m assuming projectile / bullet is the main area of immediate improvement. The cartridge itself has potential and in comparison to recognized calibers like 556 and 7.62×51 – I consider it modern *shrugs*