2-Gun Match: Chinese 7.62x39mm Bren

Thanks to the folks at SMG Guns in Texas, I just got my completed semiauto Bren gun in 7.62x39mm. What the best way to break it in? Take it to a run-n-gun match, of course!

First off, the front grip is a repro experimental piece made by IMA – it would not originally have been on the gun, but I needed a way to hold/shoot it offhand.

A brief history of the Chinese Brens…

During WWII, the Canadian Inglis factory (a privately-run enterprise) made several production run of Bren guns for Chiang Kai-Shek and his Nationalist forces. These guns were chambered in 8mm Mauser, the standard round of the Nationalist Chinese forces, and were marked on the receivers in Chinese characters:

Chinese Bren markings being scribed at the Inglis factory
Chinese Bren markings being scribed at the Inglis factory

The guns used a Canadian copy of the original Czech ZB-26/30 magazine, which held 20 rounds of 8mm ammo. These guns were used in plenty of combat actions in China, both against the Japanese and the Communist factions as well. Eventually a significant number were captured by Communist units, and after the AK rifle and its 7.62x39mm cartridge were standardized by these forces, a number of Bren guns and ZB-26 LMGs were converted by them to use the AK magazine and cartridge (similarly, many Arisaka rifles were rechambered to 7.62×39).

Chinese markings on semiauto Bren conversion
Chinese markings on semiauto Bren conversion

This conversion was fairly simple. The barrels were bored out and lined with 7.62mm liners, the ejector was lengthened, and a new magazine catch was made which held the AK magazine up against the front of the magazine well. Stock 8mm Bolts and extractors were used, as they worked adequately. In some cases, a second sear notch was cut in the gas piston, which allowed the sear to capture the bolt carrier even if it failed to travel as far back as it should. The lower gas pressure from the 39mm cartridge obviously had less reserve power for operating the Bren mechanism than the original 8×57 would have. Contrary to some claims, the gas piston and gas tube were left their original size, although the gas port in the barrel and gas regulator was enlarged.

Chinese Bren ejector converted to 7.62x39mm
Chinese Bren ejector converted to 7.62x39mm

Some thoughts after shooting this converted Bren…

It’s HEAVY. According to my scale, it’s 23 pounds, which is only about 2 pounds heavier than the Madsen LMG I shot in one of these matches a few months ago, but it’s longer and not as well balanced. Great off the bipod, but I had serious trouble shooting it standing (not that it was designed to be shot that way, of course).

Recoil in 7.62×39 is trivial. It’s possible to fire 3-5 round bursts that are actually fairly effective and accurate, because the muzzle hardly moves. Try that in a .303 semiauto Bren (or any other full-power semi) and you’ll have a much larger group, or take longer to get a small one. The big rear aperture sight stays nicely in view when you shoot, and overall it’s one of the most effective and shootable “semiauto machine guns” I’ve had a chance to play with.

Malfunctions – I had three, two caused by my ammo and one by the gun. The ammo problems were one dud primer (it had a nice sold firing pin strike) and one that hit the barrel face and stopped rather than feeding into the chamber. I was using softpoint ammo (grabbed the wrong can for the match), and the Bren certainly wasn’t designed for that (in any caliber). The gun-related problem was a case that didn’t fully eject, and got jammed between the next round being fed and the side of the receiver. This was caused by a combination of a receiver much larger than it needs to be (because of the caliber conversion) and a gas system just barely strong enough to run the gun reliably. When this malf happened I was firing from the hip instead of holding the gun solidly, and just like short-stroking a recoil operated pistol, a bit of free movement in the gun was just enough to delay ejection and cause a problem.

I was very happy to find that throughout my initial zeroing, the match, and some demo shooting afterwards, I had no other problems. The Bren was obviously built to run on much more gas pressure than the 7.62×39 cartridge generates, and I’ve seen conflicting opinions on whether this conversion would work reliably, especially with the additional striker spring required for the semiauto setup. SMG did a great job building the gun!


  1. What’s the legal situation on a gun like this? It seems to have the original receiver, so under the “once a machine gun always a machine gun” rule it’s still a class III gun even as a semi-auto conversion?

    • The receiver would have been re-welded after being torched into segments by the BATFE upon import. At that point its no longer a firearm but scrap metal. So if one re-welds it, they are manufacturing a new receiver from scrap metal. The new receiver must not allow the installation of un-modified full-auto parts, so some modifications are necessary to prevent it being classified as a machinegun. The most common method is the use of “denial pins” that prevent full-auto parts from being installed unless relieved for these pins. Newly manufactured open-bolt weapons are a no-go as well so it also must be redesigned to fire from a closed bolt thus necessitating the striker setup.

      Did I get all that right?

      • Yep. I would just clarify that the gun must be “not readily convertible” back into a machine gun, which is a fairly fully standard from ATF. Generally it means that and original fullauto fire control group cannot be possible to attach without machine shop work. In many guns that is done by adding the pins that DR mentioned. In the Browning 1919, it is generally done by having a large raised island inside the receiver. In the Bren, it’s generally done by cutting the lower assembly and welding the front part onto the receiver. In addition, there’s no legal reason not to use a hammer-fired FCG, although strikers are often simpler. I’ll be doing a video on this Bren later on that will show details of both the Chinese caliber conversion and the semiauto conversion.

    • The sights are visible as long as they are set low – but for me to zero this one using the original 8mm rear sight I need to raise it up to about 600 yards, at which point the drum blocks the sights. Frankly, the thing is heavy enough with a 30- or 40-round mag, and I’m not really interested in using an even larger mag.

      • You want to see a Russian hostage rescue done right? Look no further than here: http://www.youtube.com/watch?v=e2jfD9SGPu8

        I thought I’ll piss my pants with laughter the first time I saw that. Anyway, only those who’d survive the initial assault with the ACP’s KPVT 14.5 mm HMG going at full-auto with LONG bursts, would die in that explosion, so no sweat…

  2. Ian .. you and I will have to do a shoot-off your 7.62 vs my .303 BREN when it get here .. or maybe the BAR A3??? hehehehehehe You did pretty snappy there for a first run … I would imagine the original Chinese modified really shot well .. little heavy for a 7.62×39 (Russian 30-30!)and not a shoulder weapon of choice; but no doubt, in the hands of a person after firing 500 or so rounds could be someone to watch out for. I really loved the RPD as a in-between AR and LMG, and brought sweat to a lot of us when on the receiving end, so the 7.62×39 is good round when used as designed for. (Opinionated aren’t I!)

    • Good to hear from you, Thomas, as always. I agree, the 7.62mm x 39 is an excellent cartridge that is near-perfect for its intended role. All these decades after its introduction, the basic military-issue rounds are essentially unchanged and still highly-effective and absolutely deadly. Reminds me of those other even more venerable but still completely viable cartridges, the 7.62mm x 54R and .30-06. They might be of an older design time-wise, but are still among the best all-around cartridges in their class.

      I remember Kevin R.C. O’Brien mentioning sometime ago that in his Special Forces experience, the RPD was still one of his all-time favorites. I hope we hear from him again soon, as I haven’t seen any posts from him in recent months.

    • Good observation, Thomas! I appreciate this note from a man who stood in harm’s way and managed as you did. Also, the respect for equipment of opposition is the highest you can expect to get.

        • Hahahahaha as Ian will tell you “willing” I am, able is another thing in the running part, but off a barricade, or prone can do! Now, Ian don’t you think IF you and I are to do the shooting, grunting, groaning, burning fingers on hot brass and barrels etc … the least the OBSERVERS can do is provide the AMMO! AHHH yes .. I think a couple hundred original Ball rds of each type would cover it very nicely don’t ya think?? hahahahahahaha

  3. I like that you don’t edit out the jams/misfires. As someone who doesn’t have much contact with guns besides movies/games and the occasional skeet shooting, it really demystifies gun as the unfailable* machines popular media makes them out to be.

    *computer says spelling is wrong, but i cant figure out a good synonym for the sentence. Hope it’s not to bad.

  4. Ive been blessed to have inherited one of these 8mm Brens. Originally purchased from Interarms of Alexandria, Va. in early 1960s. The gon is marked Inglis and Bren MkII. There are no other markings or numbers (although there are serial numbers added by hand to comply wit federal law). shoots .308 nicely with a 308 barrell. would love to convert it to 7.62×39 but will not do any permanent changes to such a rare gun.The basic defecit is the 20 round mag. Any sources for a higher capacity mag. Also can you comment on the possibility that these guns (maybe a dozen imported by Interarms) were clandestine ops gun for European use and later acquired by the CIA for the Bay of Pigs operation (never delivered to the Cuban rebels. Thanks

    • As far as I know, there were never any mass-produced mags for the ZB/8mm Bren that held more than 20 rounds. There were a few experimental ones, and some home-made jobs that spliced a pair of 20s together into a 30-35 round mag.

      FWIW, conversion to 7.62×39 would not require any permanent modification. You would need a 7.62×39 barrel, an extended ejector, and a magazine catch block. Everything drops in, and you use the standard 8mm bolt and extractor.

      Actually, come to think, it might require shaving the inside of the magwell to fit the AK mags – I’m not sure about that.

      • Ian, if I understood drmarvmarv’s question well enough, he mentions the 308 conversion of the Chink Bren and not the original 8 mm gun. One magazine option in 308 is obviously the 30-rds British mag for the L4 Bren series – but that would need some reforming, I’m afraid: or at least the L4 photos show some evidence of the mag-well job (a constriction piece screwed to the side(s)?) done on them. Unfortunately that’s one of the guns I have never seen hands-on, so maybe Brit members please enlighten us on that matter. Was it necessary to convert just the 303 Brens – or all Brens have to be converted to use the 30-rd L4 mags? Cause they sure used the Chink bolt as a pattern for the L4’s (same bolt face for .30-06, .308 and 8×57).
        On the other hand – what use was air-dropping the 303 Brens to e.g. Polish underground, that you had to airdrop every round for, as well, when these Chinese Brens chambered the readily available German ammo and were available in tens of thousands?

    • drmarvmarv,
      Here are 3 possible candidates for high-capacity magazines that could be modified for your gun (assuming it is in 8mm):

      – MG13 – 25 rounds
      – 2 MG13 magazines put together – up to 50 rounds (that one might be a trifle unwieldy)
      – MG15 Doppletrommel – 75

      For some reason, any gun looks better with a VFG. Great video.

  5. Two impressions I have here. One is how agile and effective the gunner is with such a ‘pig’ (no pun). Second is my surprise how Bren is still functional when converted to ammo with 60-70% power of original round. This is a testimony to design flexibility.

    • Thanks, Denny…I’ll just say it’s a good thing that I’ve been going to the gym. 🙂

      As for the weapon running, I had my own concerns too! SMG did have to add a baffle in the flash hider to boost pressure a bit, but I’m thrilled that it runs so well. With the original full-auto guns, many had an additional sear catch cut in the bolt carrier. Since the cartridge is so much shorter than the 8×57, the bolt didn’t have to travel as far back to be reliable, and the extra sear catch would allow the gun to operate properly with what would have been a problematic short stroke in 8mm.

  6. @ Forgotten Weapons ( Ian McCollum ) and Thomas :

    I would be willing to try and help out with the cost of ammunition ( I can understand Thomas’ concerns as it can get pretty expensive, on top of travel and accommodations, etc. ) ) for a comparative “shoot-off”. There are a couple of things I’d like to know from the both of you :

    1. Ian — What 7.62mm x 39 ammunition are you using in your converted Bren? Is it standard Russian / Eastern-Bloc steel-cased FMJ with Berdan primers, brass-cased aftermarket with Boxer primers, or something else?

    2. Thomas — What 0.303″ ball ammunition are you thinking of using in your Bren? There are so many available options nowadays, so you’ll have to enlighten me.

    Last, but not least, has anyone thought of what comparable ammunition types and bullet weights in this proposed “shoot-off” will be most suitable so that there is at least some semblance of “apples to apples”? I can see that, for starters, the ammunition on both sides should be of a standard military ball-type configuration ( FMJ ), with no heavier ( or lighter ) bullet weights or differently-configured projectiles allowed ( eg., Hornady V-Max, PPU 180-grain SP, etc. ). Either standard surplus service rounds, or the modern equivalent, would seem most appropriate. With the choices available on the market today, I’m reasonably sure that a suitable compromise can be found within this context.

    Please let me know your thoughts on this subject. I would also encourage other contributors and readers to help out as well. As an old Chinese saying goes, “Many little drops make a mighty ocean”. A little bit from each and every one of us can add up to what is needed to get this done, and without financially strapping any one individual.

    • Earl … I was joking my man. BUT…I have quite enough boxes of Cal .303 Mk VII Ball to do this ditty. Each box having original 32rd. Be a little different for Ian .. But I do have original bullets for AK 47, pulled years ago, but would need the brass to load up for him. I think I could get his brass from Midway or Natchez for loading I would imagine. Travel .. Ian and I do not have a transportation plan problem, or a location problem. As Ian can explain and as I hinted at, the days of me bounding about-to-and-fro while dispensing vast accurate multiple lethal short bursts of 6 rds ea are at; I must admit an end. I can pull any bullet and replace with exact original weight FMJ and load a powder to original Mv. Let’s see what Ian says. Thanks Earl.

      • You’re welcome, Thomas — and thanks for clarifying the situation! Sounds like you’ve got everything under control, but if there’s something I can help with, please let me know and I’ll do my best from where I am ( in Florida ).

        This “shoot-off” could be very interesting if it happens.

    • Yeah, I want to know what the characters mean. I know somebody selling a full-auto version of this, and the only characters I’ve been able to decipher mean “Canada” (the first three characters of the second ‘word’)

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