What are your thoughts on CMMG barrels? I am considering one for a new build I have in mind.
I think they are excellent, but would put would put them behind BCM’s.
C4
Why is that?
I am pretty sure that they don’t use the same grade of steel and do not HPT their barrels.
C4
They are supposed to be 4150 arent they?
Not all 4150 is the same. 
Here are some questions you should always ask a barrel maker:
- What grade of steel is it (4140, 4150, etc)?
- If it is 4150, does it comply with the MIL-B-11595E spec?
- Do they HPT their barrels?
- Do they MP test their barrels AFTER they HPT them?
- Do they MP test EVERY barrel (not batches)?
- Do they allow failures (meaning what is their exit criteria)?
- Do they use M4 stamped barrel extensions (if your looking for that option)?
- Do they park. under the FSB?
- Is their FSB, F marked?
These are just some of the questions off the top of my head that I would use to compare one barrel to another.
C4
Based merely off watching Giff’s group buy go down I would not touch a CMMG barrel. Right or wrong, I think they left Giff hanging out to dry for way too long.
According to their website, they do most of the above… but, given the lack of quality I have seen with their recent barrels – or at least poor quality control – I wouldn’t touch one. There are much better choices for a new barrel.
I have a CMMG Midlength upper that I bought before BCM released theirs. It is my most accurate barrel. I compare this to two RRA and a Bushmaster. So thats not a huge sample but what I have. I got on ARF after the whole Gif thing so I don’t know anything about that. The guys at CMMG were great dealing with me on the phone. I am a casual shooter and am not in the service anymore, however I still like to buy the best quality equipment I can afford. I am Very happy with my barrel. It works great for me.I’ll probably end up with a BCM barrel someday but would have no hesitation about buying another CMMG either.
I have a 14.5" CMMG upper that has about 8500 rounds through it now and it has been 100% reliable and accurate.
My 11.5" SBR has a CMMG barrel and runs 100%, I did break a RRA bolt at about 3600 rounds on this gun. That bolt had 2000 rounds when it was used in a different AR. It headspaced fine in the CMMG barrel when I built it so I used it. It broke a lug and still ran but I immediately replaced it with a new CMT bolt. I ran this rifle at the Blackwater Carbine Operators course last month and it ran great. I could even hit the steel at 300yds. I learned a bunch at that course and like GIFFMAN went to fixed sights on this gun. I prefer seeing the sights in my peripheral vision even if I’m looking over them using the Eotechs reticle.
:eek:
I tried one of the SOCOM profile barrels because I read alot of threads stating that they were the “Uber” thing to get.
After it kept consistantly popping primers out …like… 15 or 20 out of 500 rounds fired from 4 different lots of xm-193 and a trip back to cmmg, I finally had to get my money back as it was just usless to me.
Just my .02 worth… but it was parked under the FSB, taperpins, Fmarked, M4 marked and all the other uber stuff… it just plain sucked when it came down to gun and run.
Jeff and John were very helpfull and didnt hesitate to help me. They even refunded my shipping.
The MOS barrel I replaced it with has yet to pop any primers. 
I’ve been thinking of putting a SOCM profile barrel on my DI gun. 
TS
Popping primers sounds like a headspace problem, especially if changing barrels solved the problem. Did you check the headspace on your CMMG barrel/bolt combo?
yup…
I wish that Paul made the BCM uppers in the SOCOM style. I would like to have a 14.5 upper with out paying high dollar for the COLT name/stamp on it. When will we will be seeing some BCM SOCOM Uppers?
Nope… just kept shooting it and scratching my head on why it didnt run! 
I checked it and cmmg checked it and checked everything else inbetween! Of course when they shot it, they claimed it ran fine… and it would run fine slow fire… like 1 shot every 4 - 10 seconds, but when you started to shoot rapid fire ( within 15 rounds of the first mag) it would pop primers like it was designed to do it.
Im not here to bash… but the cases all had really high pressure signs… but cmmg said it was fine… I just got my money back.
I was stuck with 2 of those barrals. Giffmann made it right with me and earned my business for a long time to come. But CMMG pretty much screwed him. I swore never to do business with CMMG again… but I’m being very tempted by their 14.5" middie barrel, which I haven’t seen ANYWHERE else, short of cutting down a 16" which I don’t really wanna do.
FWIW, I believe DPMS makes the CMMG barrels.
They do have some unique configurations and I think that is the market segment they are trying to cover. For instance I really like the idea of a 14.7" pencil barrel with M4 extensions and they are the only ones making them. Their 14.5" middies and socom weight barrels are a nice offering as well.