I was concerned about wear where the bolt carrier rides and where the cam pin nests in the upper receiver of my LMT MWS. With glasses and a magnifier I could not tell if the receiver was cracking so I put a macro lens on my camera for a closer view. It appears now that the aluminum bearing surface in the upper receiver is not smooth where the bolt carrier rides and wear is revealing casting imperfections. This upper has less than 500 rounds through it.
I am guessing this is normal, but at first I thought this might have something to do with the stock cam pin and if a POF roller cam pin would be better for operation. Has anyone here replaced their stock cam pin with a roller cam pin?
I am guessing this is normal, but at first I thought this might have something to do with the stock cam pin and if a POF roller cam pin would be better for operation. Has anyone here replaced their stock cam pin with a roller cam pin?