Loose Barrel

[survivalshop]

Checked out a CMMG 308 today because he said it would not hold a group with match ammo . Long story , short version , he tried all the things with scopes mounts & have others shoot it .

I watched as he put a new scope mount on & all was secure . @ 50 yrds. it was shooting high , brought it down into the black & then shot three more slow shots & it when back to shooting high again . I was watching with a spotting scope, I asked if he was having any problems with his trigger release & he said , they all felt good , I went over to check the mount again & found that the Barrel was loose !

Well , that was different , he asked if he should send it back to the factory & <lmao>  I took that real good  <lmao> , I'm having him come over with the rifle & we will look at it in some depth .Hay , he's my heart Doctor , gotta take care of him .

[imschur]

Wow..holy cow

[98Z5V]

ss, barrel nut loose on the upper, or do you think it might be the barrel extension OD, and the upper ID - fitment problems?

THAT sucks, new rifle, old rifle, any rifle... 

[BayouBob]

Let us know how it works out.  It will be interesting to see how many times he has too send it back to CMMG before they figure out it has a loose barrel.

[98Z5V]

It won't even go back to CMMG - I'm pretty positive that ss will take care of this himself.  <thumbsup>

[survivalshop]

New rifle bought in 2012 some time.

Won't know what's really up till he comes over , he wants to watch  & learn/know more about the rifles he owns  .

I will post photo's of the episode.

[edgecrusher]

Awesome that he's willing to learn! Bummer he got affected by a severe lack of QC at CMMG. Good luck, hope you help him out.

[unforgiven]

<thumbsup> Great

[survivalshop]

This is a different hand guard , not sure who makes it . Will post photos when all done .

Barrel nut finger tight ! Spun it off with one finger . This set up is new to me , the only wrench that will work with it is the duel DPMS/AR10 heavy duty wrench .  the AR 10 side some what fits it & will work . I have a bunch of different wrenches & this nut is different , probably proprietary to the hand guard manufacturer , but the AR 10 will do .

Photo's will tell better of whats going on . will re -assemble this weekend & post.

[imschur]

I think CMMG is now making their own handguards for many of their weapons.

[BayouBob]

They must not be big on tightening things at CMMG.  In addition to the gassing problems, mine came with all the hand guard screws loose enough that the hand guard wobbled back and forth over 1/4 inch.

[Robocop1051]

I hate to keep saying it... but at the risk of sounding elitist...

It's a [glow=red,2,300]CMMG [/glow] :puke:

[imschur]

I bought a CMMG 9mm upper the fake forward assist was damaged  from a poor packaging on Midways part. Rather than return it I contacted CMMG, emailed them a copy of my receipt. They required me to waste my time taking a picture as proof. As though I was trying to beat them out of some costly part. My time as well as theirs should have been more valuable than that exercise. Then I had to bump them over the course of a week or two to ship the replacement. I will not forget that lunacy.

[BayouBob]

They have a saying about Rossi, which I have unfortunately found to be true; "Their customers are their quality control department."  I'm beginning to think the same can be said of CMMG.

[survivalshop]

I have a Troy barrel wrench , that looks exactly like this barrel nut ,but its a smaller size.

My combo DPMS/AR10 wrench fits as shown

[survivalshop]

Here's the hand guard & how it attaches .

[survivalshop]

Put the barrel back on , lapped the upper receiver where the barrel extension flange seats & glade I did . There was a low spot where the indexing pin grove was on the upper receiver . Barrel nut went to the next hole for the gas tube on this type of barrel nut , Nice & tight & no wobble . Headspace was good

Taken her out to the range Sat. for testing, will post results.

[seasprite]

Nice job survivalshop <thumbsup>

[98Z5V]

That's a pretty solid attachment system - impressive, actually.  If that barrel nut would have been properly torqued from the factory, there's no way it would loosen up on it's own (without taking out the gas tube).

I like that design.  <thumbsup>

[survivalshop]

Wonder who makes it ?

My guess would be Troy , only because the Troy wrench I have for the 5.56 hand guard nut looks just like this nut ,but smaller dimensions as far as dia.

I will take a photo of it & you will see.

Ya never know .

[survivalshop]

Photos to follow ,but the rifle shoots very well . At 200 yards. Shot where you aimed . Much better than the one foot moa it had before I tightened the barrel .

Shooting some 145 surplus & doing about two , two & a half inch groups . I shot three rounds of my hand loads at 50 yards & have a photo , will down load them later , but a fine shooting rifle .

[survivalshop]

The 3 " orange dot is with my hand loaded 168 gr. SMK @ 50 yrds , just to see how the barrel was doing & the 8 " or bigger shoot & see ,is his 145 gr. surplus mixed in with some of my 5.56 holes.

If you look at the top of the larger target , I asked him to shoot the line at the top of the target & he came close ,one on each side , with surplus ammo no less @ 200 yrds.

Targets some how got side ways . His adj. cheek rest was too high for me to sight through his scope properly with my hand loads on the 50 yrd .line . The barre & rifle are capable of some fine shooting with the right ammo .

[gsp]

I recently bought a used cmmg mk3 that also had loose handguard screws and barrel nut. I used a strap wrench to re-tighten the barrel nut and low srength loctite for the other screws. Havent had a chance to shoot it yet.

Edited November 21, 2013 by gsp

[unforgiven]

Welcome from Indiana brother gsp.

[gsp]

Thanks