I picked mine up today.
Now to install the magazine adapter.
Done. Here it is with a D&H 7.62x39 AR15 magazine installed.
And here it is with an RZE Unimag (holds 25rds 7.62x39) installed.
That’s cool, let us know how it handles and functions.
Really neat. I appreciate the versatility of the platform. I wouldn’t mind picking one up myself.
I hope you guys have your reading glasses on.
I will try and make this as concise as I can.
I have a 7.62X39 9 inch bren 2 and an 11 inch 5.56 bren 2.
The 7.62 gun has 5180 rounds through it with approximately two hundred of those being suppressed with a dead air sandman K and a YHM Resonator K.
The gun went back to CZ at 5000 rounds for multiple failures to extract and eject.
The clear polymer mags are absolute garbage. The feed lips will break simply from use and NOT abuse. I had never dropped my two samples on concrete or dropped them loaded or even partially loaded. Purely from use, the feed lips started to spread and spider web cracks developed.
The 7.62 gun is over gassed, horribly. Brass ejects to 12:30, basically forward. Bolt velocity is way too high. Adding in a suppressor makes things worse as expected. Stove piped cases are tearing up the interior of my soft aluminum receiver. They’ve cut straight through the anodizing and are chewing the gun apart.
CZ didn’t give a shit about my warranty claim. They returned the gun with the following on the work order “Gas port and gas plug cleaned, test fire ok”. Nevermind the fact that I wrote a thesis sized letter to them documenting the failures. They did absolutely nothing to address the feedway and gassing issues. They also neglected to replace my cracked mags which I included in the shipment. Meh.
The gun is a shit box to me. I buy tools to use them, I dont buy them to use them up. We all know that AR receiver sets will last THOUSANDS of rounds. At some point, if the awful extraction and erratic ejection plus malfunctions continue, i’m eventually going to wear a fricking hole in the receiver. It’s kind of annoying to see this level of wear after only 5k rounds when I have AR15 brass deflectors that have seen upwards of 75K and look essentially brand new.
I also ran into issues with my HBI handguard causing the bolt to not go into battery. No clue what caused that but i’m not the only person. There’s a dimensional issue somewhere and the receiver is flexing to the point where it was preventing the carrier from going all the way forward. I believe this can be remedied with a lower torque spec and appropriate thread locking compound. As it stands, I’ve held off from buying any additional HBI products, not because they’re bad but because I dont trust the variance in the damned gun and I dont want to ruin my stock 556 gun since it seems to work.
My personal opinion is that the 556 gun is one of the softest shooting 556 guns ive ever shot and ive shot a shit ton of modern rifles. Its an absolute pleasure and in 1k rounds, it has been extremely reliable and really fun to shoot. The ergo’s on the american platform suck ass, as Aries mentioned. The handguard that CZ came up with for the MS version is laughably bad. I also raise an eyebrow at CZ for “forgetting” or "omitting’ or whatever lame ass excuse you want to come up with, a suppressor setting on the gas block. The American market loves suppressors and BOTH guns REALLY need a smaller gas port to deal with the increased backpressure. My 556 gun runs better than my 762 but you can definitely feel the bolt velocity increase when you slap the can on there.
I cleaned the 7.62 today and noted a few things. The “recoil rod buffer” or whatever the correct nomenclature is, is deforming. The bolt, in all of its rocket ship like velocity is beating the shit out of this part. It will eventually fail.
The ejection port is looking rough.
The plating on the recoil rod is flaking at the back of the buffer where it is slamming into the stock adapter.
The cam pin is wearing its trough in the receiver. I will be watching this as the round count continues, if the round count continues. I’m very much losing interest in the platform despite it being my grail gun, or at one time, my grail gun. On paper, it has so much to offer but id rather shoot guns than worry about my equipment disintegrating. At this time, I would wholeheartedly recommend the 556 guns. They bring a ton to the table in the way of excellent ergonomics (if you get one that works with an HBI handguard) and an amazing recoil impulse. If the aftermarket releases a suppressor gas plug, that will resolve that issue as well. Without further refinement from CZ and aftermarket advancements, spending 1600-1800 bucks on this seems like a waste when it does the same thing that an AR15 does that costs 600 bucks.
The only thing that the bren definitively does better is without a charging handle, it releases less gas to the face. I’ve tried the piston route for AR15’s and I think its a load of malarky. If you’re running a high back pressure can, you’re still going to get gas to the face regardless of operating system due to the inherent “flaw” if you will in the AR design. The open rear of the gun simply allows gas to funnel right into your face.
This gun seems to be all the rage as of late but I really question the voracity of the claims that its the best thing ever. Very few people are shooting their guns. Very few people are running their guns with high back pressure suppressors. Refer back to my first point. There are way too many people ready to declare this thing “the bees knees” after running 300 rounds through the platform…
CZ is silent on this and thus far, there is no “professional” representation from the industry that can offer up more datapoints. I’d love to see some of the prolific trainers run a sample for thousands of rounds and report back. The fact that GIGN adopted the gun means very little to me. Police and military organizations are known for making oddball decisions and their cycle of use and replacement is vastly different than a normal civilians. I want to love this gun but CZ’s downright dismissive warranty “service” leaves me with a sour taste in my mouth. Buyer beware at this current time.
I’m going to go ahead and post this and ill add photos as I have time.
Thanks you for taking the time to report in such detail.
I had a similar experience with Beretta and an ARX 100. The ONLY thing that got Beretta to take responsibility for their abortion was contacting the Better Business Bureau. That got me a phone call from their corporate office that oozed fake concern, but got me my money back.
Contact the BBB. CZUSA had their chance to make things right. They’ve shown zero integrity and deserve to have their reputation damaged as a result. They should have better oversight of warranty cases.
Magsz, In addition to what Aries144 suggested, I’d also suggest making a Youtube video. At a minimum you’ll be providing accurate information to other potential buyers. There’s a possibility that it will motivate CZ to make things right. Here’s one that I made about my Arsenal SLR-106CR. Talk about overgassed, you literally couldn’t see the cases ejecting from the rifle. Yes, it’s a low budget production, but anyone watching will get the point.
https://www.youtube.com/watch?v=H2QDsr5hzzk&t=1s
Given that your 7.62x39 Bren is severely overgassed, I think the solution is pretty simple. You need to get the gas tube (or whatever the part is that has the gas port holes) for the 14" 7.62x39. The port holes should definitely be smaller. If they’re too small, you can drill the out to the correct size with a little experimentation. If the 5.56x45 versions are interchangeable, then perhaps start with the 14" 5.56x45 one. I’m guessing that the gas tubes for the 805 and Bren 2 are not interchangeable because CZ lists the 805 gas tubes on its website, but doesn’t indicate that they’re compatible with the Bren 2. Given that CZ has the 805 gas tubes on their website, it’s likely that the Bren 2 gas tubes will follow at some point. No, you shouldn’t have to do this, but I’m just trying to help you with a solution that works.
Not to get off topic here, but I do want to share a positive experience when it comes to overgassing and the response by a company. When I bought my Swiss Arms 551LB, I found that it was severely overgassed. They actually have a chart that indicates the correct port sizes which is available on the internet. I measured the gas port holes and sure enough, they were too big. I contacted Dave at Swiss Arms in Texas who contacted Swiss Arms in Switzerland. Not only did they get me the correct gas valve, they sent everyone who had purchased a 551LB the correct gas valve. This is in spite of the fact that I was the only one who had reported the problem at the time. Swiss Arms USA is literally a one man operation, but all it took was that one man and common sense to make things right.
Bret,
Thank you for sharing your experiences, it’s appreciated.
Unfortunately, I dont think its as simple as swapping gas tubes for a multitude of reasons.
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It requires patience as the parts are not available.
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There is a user on TOS named Bisonworld that seems to know a shit ton about these weapons. I’m not sure if he works for CZ or what but he is a font of knowledge. However, he does not directly answer questions as I believe he does not want to volunteer advice that is not supported by the factory. Again, no clue who this dude is or what he does but he has way too much insider information to not be working for, having worked for or in connection with some of the engineers at CZ. He essentially states that its not as simple as swapping parts. He volunteered no other information beyond that but has said that certain combinations of gas tube, gas plugs and barrels are not compatible for whatever reason.
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I’m not an engineer. I shouldn’t have to engineer a solution to a problem that is not relegated to my sample alone. I like to tinker but there is a point where I simply give up because i’m shooting in the dark. The Bren is a far more complex mechanism than an AR15. Drilling out a gas port on that is easy from a mechanical standpoint as well as an informational standpoint. There is a TON of published information regarding gas port sizes.
I dont want to give up on the gun but right now, as I mentioned prior, I dont want to shoot a gun that is going to literally disintegrate in front of me. I guarantee that out of my warranty period, CZ will not replace the firearm, especially since i’m extremely honest and I wont lie to them when it comes to round count.
As far as a 'tube video goes. I can do something like that eventually when time allows but I honestly question the worth. I like this forum because people seem to care but if you go to Facebook, you have an entire forum/thread/group dedicated to fawning over a machine. The fanboy is particularly strong in the Bren Cult which is probably a byproduct of how rabid CZ fans are. I don’t have time or any desire to deal with unbridled bias and stupidity. I deal with it enough on a daily basis. 
Thank you again for the suggestions brother. I wish it were that easy to test.
Magsz,
Thank you for that amazing, money saving post.
Obviously, you guys can tell that i’m irked by the hopefully apparent tone in my writing. Regardless of that, I hope that my objectivity comes across as my goal behind my posts is to share my experiences with as little bias as possible.
I feel almost guilty writing what I wrote because the guns really are cool. I just don’t want to come here, post a bunch of hype filled nonsense and end up recommending something that A, costs a lot of money and B, in reality is really not any better than anything else on the market. The ONE thing that it COULD excel at, it doesn’t simply because CZ doesn’t want to acknowledge their oversight, ie the lack of a suppressor port/option.
Most of the players here are mature people that aren’t going to run out and impulse buy the latest and greatest. If you can wait, I would definitely see how the platform matures. It’s got potential but right now, I dont believe the 7.62X39 9 inch guns at least, are ready for prime time. If you do any real in depth reading on these things, it seems as though everyone reporting issues is reporting issues with the 7.62X39 9 inch guns with maybe one fella having issues with an 11 inch. I have yet to read anyone report a single failure on a 5.56 gun and I haven’t personally had one.
Hang in there guys. It’s not over but right now i’d personally direct my money elsewhere.
I’m not an engineer.
I am an industrial engineer, so I find this interesting. From a manufacturing standpoint, you want as many of the parts as possible to be the same in order to minimize inventory carrying costs, shortages, gain economies of scale in production, etc. I’ll be very surprised if the 7.62x39 gas plugs are different other than the size of the gas port holes. If something is different, it really needs to matter. Can you measure the length a diameter of your gas plug for me? If you can post a picture, that would be great.
I shouldn’t have to engineer a solution to a problem that is not relegated to my sample alone.
No doubt. There are some gunsmiths that are oriented towards fixing problems. There are others that just want to check all the boxes and call it good. CZ provided you with the latter.
As far as a 'tube video goes. I can do something like that eventually when time allows but I honestly question the worth. I like this forum because people seem to care but if you go to Facebook, you have an entire forum/thread/group dedicated to fawning over a machine. The fanboy is particularly strong in the Bren Cult which is probably a byproduct of how rabid CZ fans are. I don’t have time or any desire to deal with unbridled bias and stupidity. I deal with it enough on a daily basis.
I put up several Youtube videos showing firearms malfunctioning (and working too). 90% of the responses I get are people trying to help or thanking me for letting me know. As for the other 10%, I set my videos up so that I can delete stupid comments. I delete the comments and then block the posters. Problem solved.
Regardless of that, I hope that my objectivity comes across as my goal behind my posts is to share my experiences with as little bias as possible.
Absolutely it does.
I feel almost guilty writing what I wrote because the guns really are cool.
It’s the truth and you gave CZ the opportunity to fix it. It’s on them.
I fired my 11" 7.62x39 Bren 2Ms for the first time today. It ran 100%. Ejection was to about 3:30 with the spent cases going about 5’ to 7’. If anything, the ejection seemed weak. There were no failures though through the 140rds of Tula 122gr FMJ that was fired. I did rotate the gas plug to the adverse setting just to see if it would make a difference. It didn’t other than perhaps moving the ejection point to about 3:00. The magazines I used were a D&H 30rd, a couple of RZE Unimags and an ASC 20rd. All locked in fine and held the bolt back when they became empty.
Would I be correct to assume that the spent cases are getting chucked a good distance? If you don’t mind sharing, how far are they going?
My 14" 5.56 and 9" 7.62x39 Bren 2’s use different pistons and cylinders. I don’t know if that’s a caliber thing or a barrel length thing.
14" 5.56 on top. The 9" 7.62x39 cylinder lacks the gas vent (not pictured) at the muzzle end of the cylinder and has a larger ID, and the piston a correspondingly larger OD, compared to the 14" 5.56 parts.
You can swap them, you just have to swap both piston and cylinder.
I tried the 14" 5.56 piston/cylinder on my 9" Bren 2 and noted that it functioned with a Silencerco Omega can attached in both settings. The “Normal” 5.56 setting caused brass to barely dribble out, but without malfunction in the 60 rounds used to test it. The other setting ejected the brass somewhat gently 2-3 feet to 2-3 o’ clock. The gun failed to cycle in either setting with the can removed.
I thought I would note that my 9" Bren 2 hasn’t seen the issues Magsz gun has- but I only have a couple hundred rounds through it at this point. Mine ejects about 6+ feet to 2-3 o’ clock without can on the “Normal” gas setting and roughly the same distance to 1-2 o’ clock on the same setting with a Silencerco Omega attached.
Magsz, did your 9" Bren function fine at first and then start having problems as round count increased? Gas port erosion maybe?
Lots of really good stuff here.
Bret, let me try and find a video taken from in front of the firearm. You can see how violently the brass is being chucked forward. It’s nothing like an AK in regard to ejecting brass to the moon but it does chuck it out of there. The problem lies in the outliers when it bounces around the ejection port and then dribbles out or goes where ever it wants to go…sometimes back into the ejection port.
Bret, I agree with you from the simple standpoint of production. It makes zero sense to produce a billion different parts unless you absolutely have to which in the case of the bren, going between calibers, you may have to beyond simply drilling different port sizes. This is way beyond my intelligence level.
I can get some measurements tomorrow when I’m off duty if I have the time. I’m not really sure that the gas port would really erode in five thousand rounds. My firing schedule was not that crazy and the gun really didn’t get all that hot despite being run pretty hard. My definition of hard is that i’m not a bench shooter and 99.9% of my shooting beyond zeroing, is running drills that involve multiple rounds per evolution. The problems ‘sort’ of got progressively worse as the round count increased but that’s not really fair to say that its a gas port issue. There ARE some other factors, ie dirt, grit, changing levels of lubricant within the firearm, broken magazines that were later chucked, new magazines and tight springs etc.
I would really be curious to run the 14 inch gas piston gubbins in my 9 inch gun.
Can someone pull their 7.62X39 bolt and check tension on their extractor for me? Mine BARELY moves when probed with a glock tool. Its “clean” and free of debris but it feels like there’s a 5000000000 lb rated spring under there…
Mine is also very stiff. I haven’t noticed any issues because of this yet.
I would expect the issue encountered with an overly stiff extractor would be a failure of the bolt to go into battery, due to a failure of the extractor to snap over the rim of the feeding cartridge.
When I was shooting mine yesterday, I rotated it between another pistol and rifle. Still, the front handguard got hot to the point that it was hard to hold. I can’t imagine holding it in a military situation on full auto. Are people adding some sort of plastic handguards to these? Sorry for my ignorance, but I’m not a front rail type of person. I’ve always just purchased guns that have plastic (or wood) front handguards.
It could also lead to a situation where the gun doesn’t want to kick the brass out, or by the time the extractor lets go, the bolt is already moving forward. This could be part of the reason why the gun will stovepipe. Hmmm…
I’m willing to bet the nerves in my hands are shot from shooting so much lol! I dont really notice the heat. I’m not saying the gun doesnt get hot but it hasn’t gotten so hot that I cant hold it and if you’ve watched any of the videos on my channel, i’m not a one shot every five seconds kinda guy.
Here’s a video taken several months ago when the gun was around 3 or four thousand rounds down the tube. The ejection has gotten worse, ie more towards 12:30-1 at the current round count of ~5100. Also, in this video, the gun is ejecting in a fairly uniform way. Now, the gun will send cases in a random rainbow anywhere between 12:30 and 5.
I don’t think so. Extractor spring tension can cause failures to extract if the spring is weak enough to slip off the rim of the cartridge during extraction. It can also cause failures to go into battery if too stiff, as the extractor would fail to snap over the case rim, preventing the bolt from going into battery. The only reason it moves is to allow it to snap over a cartridge rim during feeding.
The extractor doesn’t need to, and ideally wouldn’t move at all during extraction and ejection. It acts as a stationary pivot point during ejection as the ejector pushes the cartridge off the bolt face and (hopefully) out of the ejection port.
All the evidence you’ve shown weighs pretty heavily in favor of your gun being badly overgassed. The damage to the recoil buffer, aft end of the recoil guide rod, violent 12:30 ejection, and mention of stove pipes all scream overgassed to me. The only questions left in my mind are: “Is it overgassed due to port erosion or a gas port originally drilled too large?” and “Is there anything else wrong that’s contributing to erratic ejection, like the front end of the receiver pinching the bolt carrier?”
ETA: if ejection has gotten that much worse it seems to confirm port erosion as the most likely culprit. Other thing to check would be the recoil spring. I’d be willing to bet that replacing the gas cylinder (possibly with one using a smaller set of ports) and the recoil spring would cure your issue.
CZ needs to get their shit together and get replacement parts in.
I was thinking the same thing about the recoil spring. Replacing one after several thousand rounds is reasonable. CZ not having them isn’t.