Yup, it was ammo related. I tried a few different types. Federal American Eagle, Sellier and Bellot, PMC, PMC X-TAC. Didn't like the regular PMC but the others ran fine.
CZ Bren 2 MS NON-Restricted MAJOR UPDATE Post 587
- Thread starter MarstarCanada
- Start date
Yup, it was ammo related. I tried a few different types. Federal American Eagle, Sellier and Bellot, PMC, PMC X-TAC. Didn't like the regular PMC but the others ran fine.
Probably also a little to do with the gas port on the barrel being drilled differently for the conversions. I'd wager with a little breaking-in, the PMC will also cycle.
Soviet / Russian FMJ projectiles usually have steel jacket covered with a very thin electrodeposited copper layer. It wears out the barrel lands 5-10x faster than brass / copper jackets.
I’d suggest cut up a bullet and check if the jacket (not the core) is magnetic.
Reliable / accurate / good trigger out of the box / good ergonomics / light / high quality.
These are probably the best all around AR15 ish rifle we peons can own since King Turdhole went full retard.
Thank you for the points and information my friend. I have the opportunity of jumping on a phone call today with John from marstar. I used to have the time to jump on forums and scan through YouTube for reviews before I made purchases. Time is press these days. The level of excellence and customer service that came from John today was unmatched. You're a Class Act John. Thank you for taking the time to educate me on both the keltec cmr-30 and the CZ Bren 2. Your client retention must be 110%. Thanks again looking forward to receiving them
Second this question as google fu left me with more huh than answers. If I put foot in mouth, apologize in advance.
From what I can gather, on the initial shorter gas system design, glomming around seems to put the settings for the shorter system as being in line with the manual. Namely vertical 12 o'clock as standard gas port, 45 degrees as a slightly larger adverse gas port and 90 degrees being gas off.
The MS 16" longer piston series on the US side appears to potentially have flipped the script a little, with vertical 12 o'clock being the standard but slightly larger gas port, 45 degrees being a slight step down in size of the port (potentially suppressed setting?), and a third again being a blank for shutting gas off.
Appears in both cases that third setting may also occasionally be drilled and the order of ports potentially different (think may have been the case with the 7.62 versions to get to the desired cycling).
Mine is a converted 16" MS I have (second hand, stated to be part of this run in question, if something I say raises a "they didn’t do that", apologies for further muddying waters with this post). Gas regulator is marked as a 16" version, 12 o'clock vertical appears to be an original gas port size (going off metal still having it's treatment on it). The 45 degree port and 90 degree ports appear resized (look professionally drilled and are in the white) to get progressively larger port sizes as one goes from vertical to 90 degrees.
As the conversions were tuned, would guess it was a combination of barrel port and the regulator port sizing to get things into the desired state. Don't know enough though about this platform and the conversion process to say for sure. Initial feeling though looking at the one I have is likely the 45 degree position being the smaller of the two modified ports is probably the dialed in setting. That would leave both a smaller vertical setting to reduce gas and the larger 90 degree as an adverse setting to increase gas. This is just a guess though, would be good to confirm. Middle ground default setting with options in both directions isn't a bad setup.
Knowing the 12 o'clock vertical position is the smallest of the three sizes on mine, in the absence of more info will likely go the empirical route. Start on smallest gas port setting, test, iterate until I find a sweet spot. That is probably the easiest route, see what the port sizes are on your regulator, pick a conservative starting point and adjust with rifle break in, experience, and load.
Not aure that helps but hope it does.
Rule of thumb = Start small and work your way up until it cycles correctly for the ammo you are shooting. This rule applies to ALL gas system rifles whether they are DI or piston cycled. The Last Slice summed it up best :
"Knowing the 12 o'clock vertical position is the smallest of the three sizes on mine, in the absence of more info will likely go the empirical route. Start on smallest gas port setting, test, iterate until I find a sweet spot. That is probably the easiest route, see what the port sizes are on your regulator, pick a conservative starting point and adjust with rifle break in, experience, and load."
The guns came to us with slight differences due to how they were tuned in the U.S. We modified and tuned them to run on PMC Bronze, 55 grain. It's reliable, brass cased middle of the road ammo that most folks who own a Bren 2 can probably afford so that's what we chose. If you use Barnaul, Wolf, Norinco or any other off brand or steel cased then you are on your own.
I don't feed my Porsche 87 octane from no name gas stations for a reason, don't feed your precision Czech-Wonder-Space-Gun with ex-combloc garbage ammunition.
Hope you guys are enjoying the rifles and having a great summer, here's to better times ahead.
"Knowing the 12 o'clock vertical position is the smallest of the three sizes on mine, in the absence of more info will likely go the empirical route. Start on smallest gas port setting, test, iterate until I find a sweet spot. That is probably the easiest route, see what the port sizes are on your regulator, pick a conservative starting point and adjust with rifle break in, experience, and load."
The guns came to us with slight differences due to how they were tuned in the U.S. We modified and tuned them to run on PMC Bronze, 55 grain. It's reliable, brass cased middle of the road ammo that most folks who own a Bren 2 can probably afford so that's what we chose. If you use Barnaul, Wolf, Norinco or any other off brand or steel cased then you are on your own.
I don't feed my Porsche 87 octane from no name gas stations for a reason, don't feed your precision Czech-Wonder-Space-Gun with ex-combloc garbage ammunition.
Hope you guys are enjoying the rifles and having a great summer, here's to better times ahead.
cptseawolf
CGN Regular
- Location
- Saskatchewan
This is what is in the US Manual
That's great news about testing with PMC as that's exactly what I have lots of and I think a fair choice for most shooters wanting decent ammo at a seemingly decent price comparatively. And yes we need some better times ahead after the s**t kicking we've endured. I'm looking forward to receiving my new Bren with your conversion and also looking forward to getting rid of the TURD!!! He needs a double flush!!!
No, not on the CZ-USA guns. What happened I'm guessing is that there was supposed to be a shut off (Pos 3- fully horizontal) but they messed something up and ended up drilling the 'Adverse' setting where the shut off was. This is why there is the photocopied sheet with the new amended gas settings in the box.
The eleven inch rifles were done with a two position regulator, same as you see in the owner's manual. These still have the shut off setting I believe.
Had not noticed the photocopy before. Went back to look and there it was buried deep in the cardboard box separated from the main manual. Probable outcome in my case with it changing owners and get repackaged a few times.
Scanned and attached both pages here for reference.
Attachments
Thank you! Really appreciate you taking the time to scan and attach these.
