This has been a mystery to me as to why a few of my lowers have the buffer detent hole work out. One one lower the hole is so out of round the buffer detent flies out and won't hold the buffer & spring back. Cause all kids of issues as you can imagine. I haven't been to worried about it as a $150 lower is replaceable. I was looking at my RR M16's and one of them is wearing out as well. I have halted all shooting of my M16's until I figure out what the hell could be doing it. I run H2 buffers and various LWRC lowers. I though it was my SHRIKE upper causing the issues, but I have a lower that did it before I got the SHRIKE so not sure what is doing. I will try to post pics of the hole. Any ideas what would be doing this?