CMMG MK3 308

[eah990]

so I just bought a CMMG MK3 308 about a week ago and put 30 rounds through it. This is what happened the buffer tube, so I contacted CMMG and they claim this is normal. In my mind this is absolutely not normal, and is garbage. What do you think?

 

[zoostation]

If that's normal I'd hate to see it after a thousand rounds..........

 

[BradMacc82]

Burrs on the BCG's tail.

A good polishing of the tail will make that a bad memory. I'll see if I can upload some pics from my phone to show what I mean.

 

[eah990]

that would be great. I figured the short markings going around the circumference of the buffer tube are from the retaining pin. But I cant figure out what made the two larger marks.

 

[BradMacc82]

Can't help with the 2 longer scratches, but the small ones around the buffer face - I feel safe in saying there's some type of burr on the BCG's tail.

Of course, I could always be wrong - wouldn't be the first or last time.

(Still waiting on the pictures to hit my e-mail from my phone.)

 

[BradMacc82]

Here we are -

View attachment 69911

 

[eah990]

ok thanks for posting that picture. I will take my bcg out when i get home and see if I can find any burs with my finger. Im mostly pissed CMMG customer service said it was normal, probably my last CMMG product for awhile.

 

[dist1646]

I'm thinking the longer scratches could have been made by the burr when you opened the upper from the lower.

 

[obsolete]

At least it wasn't a 3600 LWRC REPR.........like mine. The carrier can be easily fixed with some fine sand paper and a flat surface. Buffers aren't really expensive.

 

[FrankOceanXray]

A dremel set to high speed and a grinding stone.... just be real careful.

 

[eah990]

thanks for your help. You were 100% right, there is a noticeable bur on the BCG that is causing the damage. I emailed CMMG asking for a new bolt carrier group and buffer spring. I will see if they follow through.

 

[BradMacc82]

thanks for your help. You were 100% right, there is a noticeable bur on the BCG that is causing the damage. I emailed CMMG asking for a new bolt carrier group and buffer spring. I will see if they follow through.

Glad you got it figured out.

That's probably the last time I'm right this year...

 

[BenL]

thanks for your help. You were 100% right, there is a noticeable bur on the BCG that is causing the damage. I emailed CMMG asking for a new bolt carrier group and buffer spring. I will see if they follow through.

They''ll probably tell you to send the gun back (or at least the BCG.) 308 BCGs aren't cheap. Good luck.

 

[sailskidrive]

When I was 308 AR shopping I remember reading somewhere that the CMMGs also have some sort of odd dimensional compatibility issues with the other DPMS/SR25 patterned guns. I'll see if I can dig up that info if you're interested.

I've seen government M16 and M4s with marked up buffers like that...

 

[sailskidrive]

Here we are -

View attachment 69911

Is that your polished carrier or your wife's halo???

 

[huesmann]

I'm thinking the longer scratches could have been made by the burr when you opened the upper from the lower.

If that were the case, wouldn't the scratches be vertical? Unless the OP rotated the buffer manually after cracking the upper open, of course.

 

[BradMacc82]

Is that your polished carrier or your wife's halo???

BCG, Still single...

 

[Numidian]

BCG, Still single...

I'm pretty sure that was a "you're married to your hand" joke

 

[BradMacc82]

I'm pretty sure that was a "you're married to your hand" joke

Son of a..., went right over my head...