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Posted: 1/20/2008 3:55:28 AM EDT
| I am building a CAR M4 on a DPMS lower. I have heard good things about both CMMG and RRA. I can get a 16" CMMG complete upper for $525.95, or I can get a 16" RRA complete upper for $485.00. Is the CMMG better enough to justify the higher price? If I go with a 14.7" w/ perm. hider, will I lose alot in terms of accuracy? What about the 11.5" w/ perm 5.5" hider..It looks great...but will the advantages of a high quality barrel be negated by the short length? I am a highly experienced shooter (aka OLD and deaf!), and am pretty demanding about the performance of a gun I will end up dropping close to a grand on. I already shoot a Colt match HBAR, hence the want for a CAR. Opinions? |
| I've not shot a 14.7 or 11.5. But if your talking about accuracy at range ( 250 yards and out), your going to lose some velocity, which I would think is going to affect your accuracy? I am thinkg from your statement " am pretty demanding about the performance of a gun", you would want to go with the longer barrel. As to if the CMMG is better than the RRA I can't answer that one. I just recently took ouf a RRA 20" with a lower I put together, and after sight in had 5 shots easily with .75 of an inch. Seems to me most people on the site are happy with with their CMMG'S as well. |
| Thanks for the response HBAR. I should have been more specific..I will be shooting the CAR at 100yd. 99% of the time. I will use the HBAR at longer ranges. Thus velocity loss with a short barrel is not of huge concern to me. I guess the actual question would be "at 100 yd., does a short barrel cause a loss in accuracy as well as the understood loss of velocity, or are the two separate issues?" I realize sight radius will of course affect accuracy, but if I were to bench a 16" RRA or CMMG upper (scoped to eliminate the sight radius issue) at 100 yd., and do the same thing with an 11.5 w/perm 5.5 hider (also scoped), would I really notice any difference in inherent accuracy, assuming high quality ammo? Just because the bullet is traveling slower does not necessarily mean it is less accurate at the 100 yd. mark. Oh...I will be shooting Sierra 69g. handloads of very uniform quality. Matched brass, identical case length, individually weighed charges. That should eliminate much of the ammo variable inherent in the question I have posed. Of course the the original question of CMMG vs. RRA still applies. Thoughts? |
| The CMMG is worth the $. RR uses less expensive 4140 bbl steel, and CMMG uses mil spec 4150 bbl steel. That is worth the difference to me there. Someone will be along now to tell you that it does not matter and 4140 is "good enough," but I do not agree. If a better option is available for such a small difference in price, why settle for good enough when there is a better product? |
| I have a chrome lined 1\9 twist rock river\wilson 16" barrel. It shoots 1.5" @ 100yrds with 55 fmj & .68 with sierra MK 69 grainers. I believe it will do better without numb hands & gloves. I don't care for 11.5" barrels because it reduces the weapons range & you still have weapon with same overall length as a 16". Thats with the permanent 5.5" flash hider attached. A friend has 11.5" & accuacy is good. |
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The barrels RRA uses are Wilson Arms. Having handled many of both barrels, the Wilson barrels are MUCH better made overall. If you want the faster twist, on a shorter barrel buy the RRA "R4" (M4) contoured 1:7 and have it shortened and a flash hider pinned. It will probably cost the same, but you will have a better upper in the end. |
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When put in a lathe, the barrel: That has the bore in the middle of the barrel is better The barrel that has the threads close to concentric with the bore is better The barrel that does NOT look like a jump rope while turning is better The above mentioned, really doesn’t matter for blasting, but there is no question after handling thousands of barrels, which are “better”, and which simply standout as “good enough”. |
I don't own a RR so I can not comment on which is "better" but not wanting to have to pay someone to turn my barrel in a lathe to get a gov't profile is the reason I went with CMMG. It is nice to see RR come out with the lighter profile R4. If they come out with a 20" gov't profile in 1:7 I would definitley consider one some time in the future. I may even take a closer look at the R4 to replace my DPMS 16" bull barrel. |
| I have a CMMG 14.7 SOCCOM barrel..fit,finish, and straightness of bore and barrel are perfect.Accuracy excellent.The quality of the barrel as it was built to order is excellent id buy another for sure.I like RRAs parts but I think my CMMG barrel is better than theirs or Bushmaster for that matter and I used Bushy barrels all the time. |
When using the above conditions, how do the Bushmaster M4 barrels compare to the Rock River arms and CMMG? |
if you are willing to share you experiences on other brands of barrel I would love to hear it! |
How about DPMS? Assuming you have turned enough to form an opinion. |
All the brand name, production barrels are about the same. There is only 1 manufacturer that stands out on a consistant basis. |
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Quoted: All of the RRs are 1/9 twist and chrome-moly Quoted: Wrong, I'm looking at a dozen 1:7 chrome lined barrels as I type that came from Rock River. That,s Good to know I was just about to call CMMG and have them replace my RRA 1/9 twist barrel with one of there 1/7 twist barrels. The barrels your offering what is the Contour? Are they on your web site yet? |
| I think what steve is trying to say is that in the last few years i have threaded literally thousands of barrels. Many factory barrels, ie, RRA, BM, Armalite, Colt, have factory threads good enough to mount a suppressor on. Maybe 2%-5% are out of spec. From CMMG i have found that nearly 25%-35% are out of spec. Thats not exactly what i would refer to as a great track record. But thats just my observation YMMV |
I would like to thank you guys for sharing this info. There is no way for the rest of us to get a sense of these things. |
I've owned RRA & not had any issues with them, but I'm now somewhat partial to CMMG. They all do the same thing, fairly well for most brands, however, I prefer the options CMMG offers over the competition. So I think the extra cash you have to spend on the CMMG is worth it...to me. I've spent a few grand on CMMG products & I'm very pleased with their quality & function. I use 'em as duty guns & can't complain. Flip a coin. |
According to RRAMODERATOR, in this thread, Here, RRA uses 4150 bbl steel. At least in their 6.8 rifles. 
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