Solid buffer, sheared bolt catch

AR/M4 AR Technical Discussion
1

I was at the range today with some friends from the local gun club and a guy there was shooting his new SBR. The upper was a Daniels Defense 10.3 and the lower was a Stag. He said the LPK was a CMMG. The bolt catch sheared off where it comes up out of the lower and catches the bolt. It is a malfunction I have never seen before so I got curious as to what may have caused it. When he took the gun apart I noticed that it had a solid black buffer and it was completely solid hunk of metal. There were no weights inside of it so I am guessing it was a 9mm buffer. Could that have been the cause of the bolt catch breaking? Just curious, we got him a new bolt catch from spare parts stock but he doesnt want to shoot it again until we can figure out the problem.

Thanks,

2

Silly solid buffer could be part of the problem.
Low quality CMMG LPK could be the main problem.

My first AR15 was a CMMG; one of the many parts that broke was the bolt catch.

3

Is this a 5.56 SBR?

The solid buffer should be thrown into the shitcan next to the T2 buffers.

SBRs generally need good heavy buffers because they start early and open quickly.

I’d start with an H2.

An A5 is even better.

4

+1 start with a H2, and moved to a H3 at around 5,000 rounds. The barrel will be gone near 9,000 rounds anyways.