Cam pin problem

[CMP_5.56]

i have a Stag model 8 and I have about 400 rnds through and it seems as of my recent cleaning that I am having the cam pin drag problems. I am wearing a grove in my upper just after the half moon cut. So it seems I might have to go with a POF roller cam pin or the LWRC modified cam pin.

I was wondering if a heavier buffer and a stronger bolt spring would help as well?

So my questions are, has anyone else had this problem on their piston uppers?

If anyone has used the roller cam pin or the LWRC cam pin and if so have they helped?

And of course the question about the buffer and bolt spring?

[CMP_5.56]

Anybody have any advice?

Should I move this to the build it forum?

[beast556]

That is normal, every AR that I have seen has wear right there.

[Stingray]

Well used piston uppers do produce more of a groove from the cam pin flange contacting the area next to the half-moon cutout.

If you ever get a chance to examine auto uppers the "groove" will be longer and more pronounced.

[ray1970]

+1. Seems to be a normal characteristic for the AR platform.