buffer chatter

[Work]

What could cause chatter between the buffer and bolt carrier in an AR15? brand new rifle buffer, spring, and tube. less than 100 rounds through, and there are chatter marks all around where the bolt carrier contacts the buffer. Any ideas?

 

[sig1473]

Manufacturer of buffer tube and components?

 

[Hop]

It's caused by the slot on the bolt carrier that travels over the buffer retainer. Something is probably just a tad out of square. Knock off the sharp edge with a emery board or small file.

 

[Work]

UPDATE: It's the upper, not the lower. did it to a buddy's lower after putting the upper on. Could it maybe be that the bolt is seated too far in, leaving a gap between the buffer and the BCG? if there's even a 1/8" gap in there, the Bolt Carrier will be pounding the buffer every time it fires, and that could cause the chatter.

 

[DoggyDaddy]

Can you borrow your buddy's BCG to see if it still does it? Like Hop said, there might be something a little out of spec with the groove on your bolt carrier (or your BCG). At least that would either confirm or eliminate that possibility.

 

[Hop]

The sharp edge on the bcg is putting the marks on the buffer but that might not be the part that's out of square. It sure could be the takedown hole locations in the upper. It could be a lot of stuff. It's probably a tolerance stack up issue with several parts but the gun runs. Don't worry too much about it and just knock down that sharp edge and fire away.