How to Improve the Reliability of AR’s Chambered in 7.62×39

In light of recent actions from President Biden and the Department of State, this is unfortunate timing for an article I’ve been meaning to write for a few months. These new sanctions expand the scope of the Obama Administration-era Russian imports ban, focusing on the restriction of ammunition manufactured in Russia. You can read the text here.

Politics and their consequences aside, 7.62×39 is one of my favorite cartridges. I hunt hogs here in Texas almost exclusively using Tula 122 grain HP’s. Up until recently, the round was fun, easy to acquire, and affordable to shoot but that is already changing. Internet experts will often claim 7.62×39 is wildly inaccurate but this doesn’t reflect reality once you step from behind your keyboard and start shooting. While you won’t win any precision matches with it, 7.62×39 is a perfectly accurate round capable of 3-4 MOA in even the cheapest AK pattern rifles. Interestingly, I’ve been able to hold 1 MOA-sized groups using cheap Tula out of a CZ-527 bolt-action.

Why 7.62×39 in an AR-15?

The primary reason to do a 7.62×39 build was it was cheaper to shoot than 5.56. This is no longer true but there are additional benefits. 7.62×39 provides shooters with a lighter platform to launch a .30 caliber bullet from a mil-spec AR. I used to haul an AR-10 on hog-hunts and believe me that got old fast, especially when considering my shots were usually under 300 yards.

Challenges Running 7.62×39 in the AR Platform

You have 2 primary flavors to get 7.62×39 running in an AR or AR-like platform:

  1. Proprietary ‘hybrid’ AR’s chambered in 7.62×39 such as the CMMG Mutant, PSA’s KS-47, and the LAR-47 from Rock River Arms. These use many milspec AR components but often incorporate a proprietary lower receiver to accept AK magazines. This is a different class of rifle that is outside the scope of this article.
  2. Building one using a milspec AR lower receiver using specialized magazines designed to accommodate an AR style magazine. This is the type of rifle I will focus on in this article.

Problem 1: Feeding Issues

Building a 7.62×39 AR with a milspec lower involves simply changing the bolt, barrel, and magazine. There are many magazine offerings from ASC, AR Stoner, E-Lander, and others that have seen mixed results in reliably feeding the round.

A cursory search will land you in multiple echo chambers of folks saying this build can’t be done due to the round’s taper responsible for the iconic curve found in AK mags. This taper presents a challenge in AR mags causing consistent feeding issues The cartridge’s geometry just doesn’t play nicely with AR magazine dimensions.

Enter the C-Products Duramag.

C-Products Duramags are the Gold Standard in Reliability

The C-Products Duramag 7.62×39 magazine is uniformly considered the best magazine option for your build. They allow for easy insertion into an AR magwell while flaring out to accommodate the round’s taper and feature an improved follower to facilitate consistent feeding. I exclusively use these and have had zero FTF’s in thousands of rounds. Failures to feed represent probably 95% of the challenge in getting this build up and running and these Duramags run like a clock.

Issue 2: Failures to Fire

Steel cased 7.62×39 rounds have notoriously hard primers making it difficult for a standard firing pin to consistently engage the primer. Light primer strikes are another common complaint. Few things are as disheartening as hearing an audible click in the middle of a mag dump.

Few things are as satisfying as ripping thru a magazine of 7.62×39

4 years ago, a common hack to solve for this was to take a Dremel to the neck of your firing pin and remove imprecise amounts of material to allow the firing pin to extend deeper into the primer once the hammer comes into contact with it. This was an inconsistent and probably not the safest approach.

Well, the market provides. You can easily buy an enhanced 7.62×39 firing pin for $7-$10 that provides incrementally more penetration on hard primers.

Nowadays, enhanced firing pins come stock with most 7.62×39 BCG’s. Reputable 7.62×39 BCG’s that I have experience with include AimSurplus, Brownells, and ToolCraft.

Issue 3: Accelerated Bolt Wear

Steel cased ammo is harder on your bolt. In particular, your extractor is prone to wear. Unfortunately, there’s no solution for this. It’s kind of an operational cost. However, when available complete BCG’s from reputable manufacturers typically run $130-$160. You can also pick up spare bolts for $60-$90 and spare extractors. I personally went the route to load up on spare complete BCG’s and bolts.

As far as reliability goes, AimSurplus makes the most well-regarded 7.62×39 BCG but it has rarely been in stock for the last year.

Conclusion

7.62×39 is an impressive round that too often gets written off as being only good for magdumps and plinking. I use it on hogs and whitetail with excellent results and it’s ballistically comparable to 30-30. I love this round chambered in the familiar AR platform because it gives you a bit more power in a lighter package. While it’s been a challenge to get these to function properly, if you have the right components you can easily put one of these together.

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About the author: CitizenHush is the Bob Ross of 2A Twitter. A Virginian by birth but Texan by the Grace of God, Mr. Hush enjoys firearms and firearm technology.Dislikes include: Strong opinions on Cast Iron skillets, politicians, and Brass Goblins. When he’s not blasting feral hogs in Central Texas, you can find him either on the range or living his best life as a suburban ranch hand.

{ 19 comments… add one }
  • HockeyJoe58 September 7, 2022, 7:56 am

    I have several AR15 7.62×39 builds that I’ve played with for the past few years. A lot of what you’ve mentioned has held true for me as well. C-Products/Duramag magazines run flawlessly in every build. ASC’s have caused me problems. Accuracy with steel case ammo is consistently 1.5 MOA in builds with 16″ barrels, around 2 MOA in a 8″ build (which is incredibly fun to shoot at Practical Rifle matches). That was my biggest and most pleasant surprise. I too have had success with AIM BCG’s, with my most recent being toolcraft, all with enhanced firing pin. I’ve had 2 broken extractors, which I write off to being a part of the game. Summary, once you work out the minor issues, you wind up with a very reliable & accurate firearm that gives you another option to use when ammo gets scarce, or just for fun.

  • olddog January 10, 2022, 6:36 am

    I own 3 ARs chambered in 7.62 x 39 You hit the nail right on the head C products DuraMag, enhanced firing pin and strong hammer spring Have one AR 47 set up with 11.5″ chrome lined bbl and ITF Defense binary trigger It is super reliable and a hoot to shoot.

  • Give Me Freedom November 2, 2021, 10:32 pm

    Almost all my AR-15 7.62 x 39 magazines are C-Products brand. They work great with my rifle. I mostly have thirty round full capacity magazines but I also have some twenty round ones.

    I like the 7.62 x 39 round. It hits harder than 5.56 x 45 out to around 275 yards.

    I like rifle rounds to be at least 6.5 millimeter in caliber, around 2,200 feet per second in muzzle velocity and faster, and at least 95 grains in bullet weight.

  • Anonsidious November 2, 2021, 7:05 pm

    Back in my day we chambered everything in .38 special. All we needed. Thank you your review young man but Im happy with my 38 by 38 special.

  • kb31416 November 2, 2021, 3:58 pm

    I built a 16″ AR in 7.62×39 with an A2 upper with normal A2 adjustable sights. The purpose was to test in a 200 yard fun match that our range puts on in the winter. The objective was to test the AR platform vs the AK platform.
    C-Products Duramags (10 round), enhanced/stronger hammer spring, and PSA BCG, including the longer firing pin.
    The result is that the AR was much more accurate than an AK at 200 yards, not even close.
    Some other comments:
    1. 7.62×39 much more potent than the 300 AAC.
    2. Testing was with crappy mil-surp loose packed ammo made in the 70s. It was CORROSIVE, and my initial cleaning was ineffective, resulting in a rusty bore. I cleaned it now, but it’s still messed up. Even messed up, it still shoots fine.
    3. I have and reload for 300 AAC and 7.62×40, and enjoy using both for deer, all supersonic (can’t have cans in IL). With this said, the 300 AAC is much less potent than either the x40 or x39. Not apples to apples.
    I like them all.
    4. I have a ton of AK ammo from when it was inexpensive, so that was also an impetus to build the AR for it. AKs and SKSs are great, but the AR is hands down better, so I am glad that they are the weapons of my enemy (at least until the usurper gave AR type weapons to the Taliban).
    Let’s go Brandon.

  • Alan Luebbert November 1, 2021, 2:20 pm

    I bought lower from a friend of mine and it was stamped 7.62 X39. I installed 5.56 upper on it for a while but I got bored. I ordered a Stoner 7.62X39 upper from Midway. I use a Bushnell 3X9X40 scope to get 1” groups at 100 yards. Missouri hunting regulations are that magazines with 10 rounds or less for hunting. I have a few 20’s but they don’t get used very often. I have never run steel cased ammunition in my rifle. Hornady has .312 bullets that help shoot those groups. A target grade trigger upgrade is essential for success as well.
    Happy Hunting!

  • Timm November 1, 2021, 10:56 am

    Thanks for the review.

  • Michael Cooke November 1, 2021, 10:51 am

    Good article.

    I built one of these starting with a free barrel I got from BCA on Veterans Day a few years back. I agree with the C-Products mags (I have three thus far), as well as the purpose-built BCG. I went with BCA’s side-charging upper to keep things as similar to the AK/SKS platform as possible. Topped it off with a Luth-AR MBR2 stock.

    I replaced the hammer with a heavier hammer to facilitate more reliable functionality; haven’t had a FTFire since.

  • Bob November 1, 2021, 10:26 am

    I use ASC magazines (that were recommended somewhere when I started the build) and I’ve never had any feeding issues.

  • Jake November 1, 2021, 9:58 am

    The Duramags are excellent and reliable. I’ve also had good luck with some USA “Frankenmags” (AR top mated to AK bottom) for twenty years. I don’t know if they sell them any more but I got the Colt 7.62 upper years ago. Never a problem after the first few rounds to loosen it up. I do not use steel in my Colt but Winchester, Federal, Remington, Fiocchi, PPU, GECO and Norma brass rounds will drive tacks from the Colts and SIGs. The SIG is especially cool using AK mags.

  • Jay Smith November 1, 2021, 9:41 am

    I have an STI made AR in 7.62×39 w/ a 3×9. Kind of wished I had waited & got a hybrid piston type ) No ftf problems ( other than trying to use subsonic rounds w/suppressor . Yes , i know – backgassing /blowback ,) . I use a hvy ( 7.62×51) spring and St steel weighted buffer to reduce wear on bolt) Not to mention , the suppressor use utterly destroyed the aluminium buffer it came with… . Got a stiff , fluted matte st steel bbl & accuracy is good to 350yds for chest sized targets ( better closer obviously & beyond that good for suppression fire . ) Yes , I know , AKs are piston driven ( I also have a Galil ) , but the suppressor throws the bullet poi 10-11 inches high/right consistently at 150 yds ( no baffle strikes ) , barrel whip ? So , that one has a red dot with a good comp.

    • Jay Smith November 1, 2021, 9:45 am

      Pretty sure all my mags are ASC . ?

  • Ed Thaxton November 1, 2021, 9:16 am

    Couldn’t agree more. Thanks for the Duramag note!. I have several 7.62×39 AR uppers, on stock lowers. They shoot just fine. 7.62×39 is MUCH better for my needs than 5.56×45.

  • Evan November 1, 2021, 9:00 am

    Since .300 Blackout became a thing, chambering an AR in 7.62×39 has been pointless. Just build it in .300 Blackout, you’ll get the same performance, and the cartridge was specifically designed for use with the AR platform.

    • Ed Thaxton November 1, 2021, 9:23 am

      300 Blackout is much more expensive than 7.62×39, and should never have been developed. A round that can chamber in a firearm should not destroy it and injure/kill the operator. Sure, one can manage this with caution and care, but the 357/38 approach is much better.

    • Bryant November 1, 2021, 9:40 am

      Except that .300 Blackout is anywhere 50%-100% more/round & still not found near as regularly found on LGS shelves.

    • Jay Smith November 1, 2021, 9:47 am

      Agree with AK ammo being cheaper / easier to get than .300 b & i wanted ammo commonality with my Galil .

    • Jake November 1, 2021, 10:23 am

      In my opinion the 300 Blackout/7.62×35 is a good way to turn an AR into an M1 Carbine ballistically. If you want performance, the Wilson 7.62×40 is the way to go. I am surprised no one has come out with a + P or juiced up load in 7.62×39 to use with western rifles which can take 10-15,000 lbs. more pressure than an AK.

    • David November 1, 2021, 1:37 pm

      I handload 7.62×39 to impressive levels of performance. It’s truly a great little round. The 300 crap out was intended to be a subsonic round and has not the case space to load it to comparable pressures. Also running brass loads negates the need for replacing worn bolt items.

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