Bren 2 9" FTE/Stovepipe issues

[czfanatic_]

Alright guys, time to pump the brakes on my idea for now. 

I put ~400 rounds total yesterday through the gun, with zero failures, but on the final mag I broke the extractor. 

Not sure if it was the spring that caused it, but I would assume so. 

I called CZ and they are going to send me a new extractor if they can find one... I should know tomorrow. 

Edit:  I should mention that the current round count on the gun is approximately 2900. 

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[1350survivor]

I see you have the extractor donut installed which might cause issues. Usually the donut is not needed with the stiffer 5-coil extractor springs, and the Bren 2 extractor did not come with a donut installed either

[czfanatic_]

I see you have the extractor donut installed which might cause issues. Usually the donut is not needed with the stiffer 5-coil extractor springs, and the Bren 2 extractor did not come with a donut installed either

Yeah, that is probably what broke my extractor

[MeatAxe]

I see you have the extractor donut installed which might cause issues. Usually the donut is not needed with the stiffer 5-coil extractor springs, and the Bren 2 extractor did not come with a donut installed either

Yeah, that is probably what broke my extractor

Alright guys, time to pump the brakes on my idea for now. 

I put ~400 rounds total yesterday through the gun, with zero failures, but on the final mag I broke the extractor. 

Not sure if it was the spring that caused it, but I would assume so. 

I called CZ and they are going to send me a new extractor if they can find one... I should know tomorrow. 

Edit:  I should mention that the current round count on the gun is approximately 2900. 

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Thanks for going to the effort to deepen the pool of knowledge here!

So maybe just the BCM extractor spring will fix the problem...

It's really unforgivable that CZ isn't stocking ANY parts for the Bren 2 after a year or two of importing them to the US.

[America_First]

Well I'll have my spring kit on stand by until some extractors are imported and available for purchase. 

I'm going to run another 200 - 250 rounds through mine with the charging handle on the right hand side, this just seems to stand out to me as when I changed my grip to behind the charging handle (thumb no longer placing pressure against it, which likely unlocked it) there were no more malfunctions.  Ejection was fairly consistent with Golden Tiger.  2-ish 'o' clock. 

This is almost comical, how are they selling $1,600 - $2,000 firearms without any spare parts here in the United States? 

[czfanatic_]

Thanks for going to the effort to deepen the pool of knowledge here!

So maybe just the BCM extractor spring will fix the problem...

It's really unforgivable that CZ isn't stocking ANY parts for the Bren 2 after a year or two of importing them to the US.

Hey, no problem!  I've got two Bren 2's for a few reasons... I love them, and it also means that I can break one and still have one available to shoot!  I just can't afford to shoot 5.56, haha!

When I called CZ, the guy said that their "Bren 2 parts guy" was out for the day.  I guess they've only got one person for this. 

I think omitting the o-ring would prevent any damage from occurring to the extractor.  The spring alone wouldn't cause *that* much more pressure.

I'm going to run my friends extractor in my gun this week, and his is basically brand new.  I'm assuming the gun will shoot like new, but who knows at this point.

It was literally flawless for almost 2.5k rounds, and then this crap starts happening like a light switch got flipped.

I tell you though, that gun ran like a boss for 400 rounds with that spring and o-ring in there 

Well I'll have my spring kit on stand by until some extractors are imported and available for purchase. 

I'm going to run another 200 - 250 rounds through mine with the charging handle on the right hand side, this just seems to stand out to me as when I changed my grip to behind the charging handle (thumb no longer placing pressure against it, which likely unlocked it) there were no more malfunctions.  Ejection was fairly consistent with Golden Tiger.  2-ish 'o' clock. 

This is almost comical, how are they selling $1,600 - $2,000 firearms without any spare parts here in the United States?

I'll let you know more tomorrow, I'm going to try to talk to "the Bren 2 parts guy" and see if he is even willing to admit to there possibly being an issue with these guns.  I'm going to try and convince him to send me more than one extractor as well in case this happens in another few months.


I really hope the root of this issue is a bad batch of extractors. 

[America_First]

CZ-USA knows there is a problem but they believe it's due to commercial ammunition [we know it's not], this is what they told me today. 

"Talking to our Technical Support Gunsmiths, they've seen a handful of Bren 2 7.62x39s with a mix of issues causing the rifle to run a bit sluggishly. Clogged gas ports and chambers laden with varnish were the main culprits, though with quality ammo even those super dirty rifles ran well. We've had one rifle through that had been subjected to some seriously hot stuff, with tons of wear on its springs and buffer. Replacement of the worn parts and it ran as it should.
As with anything, quality ammo will go a long way. Steel-cased ammo will increase wear and tear, so the expectation is that a bit more maintenance may be a reality."

They are so far off base right now.  I contacted CZ-EU as well, waiting on their response.

[czfanatic_]

CZ-USA knows there is a problem but they believe it's due to commercial ammunition [we know it's not], this is what they told me today. 

"Talking to our Technical Support Gunsmiths, they've seen a handful of Bren 2 7.62x39s with a mix of issues causing the rifle to run a bit sluggishly. Clogged gas ports and chambers laden with varnish were the main culprits, though with quality ammo even those super dirty rifles ran well. We've had one rifle through that had been subjected to some seriously hot stuff, with tons of wear on its springs and buffer. Replacement of the worn parts and it ran as it should.
As with anything, quality ammo will go a long way. Steel-cased ammo will increase wear and tear, so the expectation is that a bit more maintenance may be a reality."

They are so far off base right now.  I contacted CZ-EU as well, waiting on their response.

If the gun can't run steel cased ammo reliably then there was no point of bringing this gun to the American market in my opinion.  We aren't rolling around like GIGN with Hornady 7.62x39 in our guns all the time. 

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[America_First]

CZ-USA knows there is a problem but they believe it's due to commercial ammunition [we know it's not], this is what they told me today. 

"Talking to our Technical Support Gunsmiths, they've seen a handful of Bren 2 7.62x39s with a mix of issues causing the rifle to run a bit sluggishly. Clogged gas ports and chambers laden with varnish were the main culprits, though with quality ammo even those super dirty rifles ran well. We've had one rifle through that had been subjected to some seriously hot stuff, with tons of wear on its springs and buffer. Replacement of the worn parts and it ran as it should.
As with anything, quality ammo will go a long way. Steel-cased ammo will increase wear and tear, so the expectation is that a bit more maintenance may be a reality."

They are so far off base right now.  I contacted CZ-EU as well, waiting on their response.

If the gun can't run steel cased ammo reliably then there was no point of bringing this gun to the American market in my opinion.  We aren't rolling around like GIGN with Hornady 7.62x39 in our guns all the time. 

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Like I said, they are clueless right now.  You're absolutely correct, I think you're on to something however that they need to tune (increase spring pressure) on the extractor to run reliably with steel cased ammunition. 

I let them know that they're going to obtain a reputation for the Bren 2S (Ms) in 7.62x39 as being unreliable, if they don't engineer a solution to this problem quickly. 

[MeatAxe]

^As much as I love the Bren 2, the ergonomics, light handling, modularity w/ optics, accuracy and (for me, thus far) reliability, I can’t use it as a go to, first tier shtf weapon because it has no parts or service back up from CZ, even after @ 2 years of imports into the USA. Inexcusable.

I can’t keep track of the people having failures to extract / eject issues with the Bren 2, but it seems that all   have 7.62x39 guns and (most) have fitted aftermarket hand guards and / or rail plates... may have to do a poll, though I’m no inter web genus....

[Aries144]

The rubber extractor spring O-ring was introduced to address extraction failures in M4s. The cause of those extraction failures? Premature unlocking while chamber pressure was higher than optimal. What caused the bolt to unlock too early? Gas port erosion causing the carbines to become over gassed after some thousands of rounds fired.

It's interesting to note that when midlength gas systems were introduced to 16" bbl AR15s, the need for extractor o-rings went away. Why? The midlength gas system essentially allows unlocking to happen later, when chamber pressure is lower, making extraction easier. The port is also farther from the chamber, meaning it doesn't enlarge as quickly over the life of the barrel due to port erosion.

Want to know some more symptoms of an overgassed gun? Bolt over base malfunctions, stovepipe failures with the mouth of the case pointing into the receiver (in guns with plunger ejectors),  violent ejection, and excessive peaning of the rear of the bolt carrier, fire control group, and components impacted by the bolt carrier at its rear of travel.

The 9" 7.62x39 guns are badly overgassed. Springs can't fix that. You have to reduce the size of the gas port.

[Magsz]

CZ-USA knows there is a problem but they believe it's due to commercial ammunition [we know it's not], this is what they told me today. 

"Talking to our Technical Support Gunsmiths, they've seen a handful of Bren 2 7.62x39s with a mix of issues causing the rifle to run a bit sluggishly. Clogged gas ports and chambers laden with varnish were the main culprits, though with quality ammo even those super dirty rifles ran well. We've had one rifle through that had been subjected to some seriously hot stuff, with tons of wear on its springs and buffer. Replacement of the worn parts and it ran as it should.
As with anything, quality ammo will go a long way. Steel-cased ammo will increase wear and tear, so the expectation is that a bit more maintenance may be a reality."

They are so far off base right now.  I contacted CZ-EU as well, waiting on their response.

That is such a steaming pile of DUNG response right there.  They're passing the buck and its complete garbage.  You (CZ) went out of your way to make a garbage Americanized version of a rifle.  The fact that they state that its an ammo related issue and their baby is perfect in every way is about as dismissive as a company can be.  They're also perpetuating bullbleep myths that have been disprove time and again.  Increased wear?  Yeah...the only thing that wears is the barrel itself due to the bimetal bullets.

I hadn't shot anything but polymer coated steel through my gun when it started having issues so the whole "varnish" excuse is pure bullbleep to me.  The polymer does not "melt" off of the steel resulting in a dirty or fouled chamber.  There are PSA AR15's that can run steel cased .223 fo THOUSANDS of rounds without issue with no cleaning and only lubricant being added.

Also "clogged gas ports".  What the FUDGE are they talking about?  I haven't measured it but carrier velocity on my gun never decreased as I neared FIVE THOUSAND rounds.  In fact, the gun just became even more unreliable and erratic in its ejection pattern.  This gun has NEVER, EVER had anything close to a sluggish bolt.  EVER.

They're literally just saying bleep at this point to make noise.  This is seriously irritating.

[czfanatic_]

I do see that there are lots of folks with aftermarket hand guards who have this issue, but I almost have to wonder if there is a correlation between people with these handguards, and people who actually shoot their guns a lot. 

I have 2.5k rounds flawlessly through the gun with the handguard installed.  Not sure why it would cause problems only after that many rounds. 

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[Aries144]

Either this is purposeful obfuscation, or the people they have looking at people's returned firearms are just incompetent. I'm inclined to think it's the latter.

[czfanatic_]

I'm hell bent on getting this rifle to run reliably.  I will even get a new gas port drilled in the "0" setting that is smaller to test overgassing theories. 

I am gonna call my buddy in the Czech Republic later today who works for a CZ LE dealer and see if he knows of anything regarding these guns on that side of the pond.

I should also be able to talk to the CZ-USA "Bren 2 Parts Guy" today.  I'll see what I can pull out of him.