I know CMMG sells a 14.5" barrel w/ a mid legth gas tube. This sounds good, compact barrel with the longer gas tube for a less violent action cycle but I wonder about It's reliability as that is my primary requirement.
TIA,
G45
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I know CMMG sells a 14.5" barrel w/ a mid legth gas tube. This sounds good, compact barrel with the longer gas tube for a less violent action cycle but I wonder about It's reliability as that is my primary requirement.
TIA,
G45
If you are asking if a mid-length is better that a carbine length tube, then the answer would be.....IMHO, yes.
Well, CMMG screwed up the headspacing on mine, but now that I've gotten that fixed, it runs just great. Gas tube length isn't an issue.
A midlength 14.5 barrel is on my list of things to get for sure. Everyone who has one says it works great. There's much more dwell time than an 11.5 inch commando barrel.
I just would NEVER consider a CMMG. Way too hit and miss in the QC department.
I have had three 14.5" midlengths. All have been 100% reliable.
http://www.bravocompanyusa.com/Sabre...ed%2050385.htm
I'd be all over that if it only had the factory FSB installed.:(
OK, CMMG no go and 14.5"barrel with midlength gastube good to go.
Thanks,
G45
Didn’t a very prominent moderator here say it was a clue that people were going away from 14.5 middys do to problems ?
I believe the problem with the middy's had to do with the proximity of the gas port to the muzzle. IIRC the close proximity causes premature errosion in the gas port hole.
This info was incorrect. The short gas system is the one that is known to have gas port issues
I believe I've seen something like that, either here or on a different website, but no specifics or sample size were provided. I've read on this website not to use an excessively heavy buffer with 14.5 middys, especially in cold weather.
To date I've only read reports from individual users, most of them with sample size of 1 or 2, and I've not found negative reports so far. I've not seen large sample size-large volume of fire reports.
Gas port on 14.5 middy is over 5 inches away from muzzle, which similar or longer than most SBRs. Are SBRs more prone to gas port erosion?
I've recently had one of my 16 inch middies cut down to 14.5 as an experiment. So far so good, but the round count is low. I plan on taking through what is supposed to be a voluminous round count class, we'll see.
I had a 16" LMT MRP barrel w/middy gas system that I had cut down to 14.5". I put over 6k thru it since having it chopped, and never had a cycling or reliability issue that was caused by the barrel/gas system combo.
I got rid of it last year, and the current owner recently told me that it still runs like a top. I replaced it with a Noveske 14.5" Afghan middy which so far has been 100%
I ordered a 14.5" Mid Length Gas Stripped Barrel manufactured by Sabre Defense Industries. I will measure the port size before I build it up and report back.
Thanks for all of the replies!
John
Indeed. The previous reply doesn't make sense at all. The farther away from the chamber, the lower the port erosion rate as I understand it.
Port erosion is a carbine gas system issue. And from what some of the Armorors here have stated it's somewhat self limiting.
There's more than enough barrel past the port on a 14.5 middy to make it run right. Shit. I've seen 16" barrels with a rifle gas system that will work.
New to M4Carbine, but have been lurking for quite a while. This is my first post here. I was glad to see this thread come up.
I recently finished a build using a 14.5" CMMG lightweight midlength barrel. It was everything I hoped it would be for weight. Problem is, it would not cycle when I took it out to shoot for the first time. The bolt cycles far enough to cock the hammer, but does not eject or load any subsequent round. I am quite certain this is attributable to a gas problem.
I checked the bolt carrier key for proper installation. It appears to be properly aligned with the gas tube and is not binding. The gas tube is pinned and does not appear to be leaking. Gas rings are properly installed - I checked the bolt and bolt carrier in another gun and it functioned fine.
The only two possibilities I can think of are 1) ammo (I was using the .223 Centurion ammo bought from Aim - I will be trying LC M193 next time out), and 2) problem with the gas port. This is my sixth build, and I have never had a problem with a gun functioning properly. I have used CMMG on two other rifles and never had a problem. Any input would be appreciated.
1811guy,
I really think the Centurion ammo is the problem. I put thousands of rounds of M193 through a CMMG 14.5" mid-length and never had a malfunction.
I don't agree. I haven't heard a single issue with Centurion ammo. The same can not be said for CMMG.
Centurion is plain jane .223, and it should run.... especially on a middy.
I think the problem is not with CMMG's parts, but with their QC post/during assembly. I've seen multiple problems on multiple CMMG guns that could have been avoided by a 30 second scan of the gun, and were immediately spotted by the buyer. Hell, they sent me mine missing parts.
CMMG makes great parts. These days, that's as far as I'd trust them...in my house, CMMG is a four letter word.
I have not tried Centurion ammo but I did read this on another site:
i purchased 1000 rounds of centurion from atg and would not buy again.out of the first few clips i noticed seating depth was all over the place some would not even fit into the mag (cproducts stainless).then the wife was shooting and bang bang bang nothing. i took the weapon and tried to pull the charge handle with no luck. dropped the mag seperated the lowers took a screwdriver to gently pry back the bolt and i found a live round with a case neck that was badly bent. i then hand picked each round for the rest of the day which worked great. however i ended up throwing away approx 50 rounds that day that had bent case necks,improper seating depth that was way off or case necks that were doubled over. one of the bullets i was able to easily hand pull out of the case. i have approx 400 rounds left and after sorting them i found another 20 rounds that are toast. buyer beware the QA process from centurion is less than acceptable go with prvi or federal.
any leaks around the FSB? What are you using for buffer and spring? Does it fail to cycle everytime or sometimes?
No gas leaks. I am running a mil-spec recoil spring with standard buffer. It fails to cycle every time. I presently have a bolt action AR.:(
The only thing from CMMG is the barrel assy. How bad could someone screw that up? I am wondering if the problem is under the FSB with the gas port. I bought the barrel back in October before the post election frenzy and assembled the rifle just 2 weeks ago. I am dreading calling CMMG because I have heard their CS blows right now. Anyway, thanks for the replies guys.
They screwed up my barrel assembly; improper headspace on the barrel extension. Just saying it's not impossible.
Something to think about when troubleshooting. Yes, the ammo may be fine or maybe it isn't rather than spend needless amounts of money and dicking around it is highly advisable to procure some other well-known ammo and test it. Every ammo manufacturer has put out crappy ammo before, just like every top line gun maker has rolled out a lemon.
So, the first thing I would do is get some other ammo, probably two different types and shoot it. Second, I would then check and see if there is any change that you may have made that could have caused the issue. We see it here all the time. Somebody got a cool guy buffer, a super duper high power spring and the latest multi-cool this or that and then their weapon quit running. Make sure that you mags are good to go as well.
If that fails then contact CMMG, explain the problem and articulate to them the steps that you have taken to fix the problem. At that point send it back if necessary.
MANUFACTURERS WILL CONTINUE TO BUILD AND SELL CRAP UNLESS THEY ARE HELD ACCOUNTABLE. IF YOU DON'T ADDRESS THE ISSUE THEY WON'T FIX IT.
I've seen several too. If you look at the dissy threads on ARF there's a few guys that run this system.
I have an instructor who is running this exact set up. I'm skeptical of it. I'm building a dissy style gun now with a middy shaved gas block under rifle handguards with the FSB in the rifle position.
i thought the definition of a dissy was a barrel that used an fsb at rifle length but used a carbine gas (didn't ever understand why it wasn't a middy gas).
anyway, i knew about dissys just didn't know that you could run a rifle length gas on a 16" the least i'd heard of was 17" barrel with a rifle length gas system, i this is a popular lilja that's made or something.
Funny. I thought the definition of a dissipator was a barrel as short as would run reliably with a rifle-length gas system, so that much of the recoil was "dissipated".
Well, it seems to run fine with LC M193 ammo. I would prefer it works with .223 ammo as well given that LC M193 does not grow on trees anymore. Would opening the gas port up help any? Or should I just leave well enough alone?
I'd get it checked out. It should easily run .223 ammo. I wouldn't just open the port without determining for sure that it was needed.
Here is an update on the rifle:
I was unable to get any response from CMMG customer service by e-mail or phone. I decided to remove the FSB to see if there was any visible problem. While trying to drive our the taper pins I learned that CMMG does not use hardened steel pins. The pins were like butter and despite my best efforts and care they just became more and more deformed. I finally took a 1/16" drill bit and bored a hole half way through the pins. It was like drilling through aluminum. I then used the same drill bit as a punch. This put the driving force of my hits lower on the pins and they finally came out.
I could see where gas was leaking from the port under the FSB and toward the handguards. I surmised that because the CMMG pins were so soft, they were unable to make a tight seal between the barrel and FSB. The pins essentially push down on the FSB and up on the barrel creating a tight seal. The CMMG pins were doing nothing more than holding the FSB on. I re-attached the FSB using Colt pins I ordered from Brownell's. The pins were noticeably better in quality and while being driven in did not squish in place like the CMMG pins. Back to the range - cycled the .223 ammo without a problem.
While I will never buy another CMMG product again because of their customer service, I do feel that the barrel is decent - I get good groups with it, and it is made from CV steel. The FSB is F marked - looks to be a standard mil-spec part. The permanently attached FH was done properly and is properly timed. Headspacing is right on. I am a bit confused as to why CMMG would use something other than a mil-spec taper pin given that it is such an inexpensive part.
If I could have found another company that makes a lightweight 14.5" midlength barrel I would have considered them. The closest I could find was Noveske, but I wanted a lightweight profile. Live and learn.