forget it

Are you talking about the wear inside the upper receiver where the cam pin rubs? If so that exist in most if not all Ar15's. Even the DI guns have the same wears.

My AA kit dug a small trough at this location, no effect on function whatsoever.

The damage is coming from the skis and the roller cam. I have seen slight shavings out of my DI but this is ecsessive. I have shot over a 1k rounds and it still does it compared to my DI. Any thoughts or should I complain to Adams Arms. Also does the spring in the BCG have any impact on this. Sorry no pic just yet been working 16 hours days all week.

Lets see some pics , its much easier to tell if its usual wear or extreme.

Hmm, my upper looks like the last picture.

My bolt carrier looks different from that one, maybe that's an older bc? Also I don't work for AA.

Mine looks just like this one:


I think yours is the older generation/model like this one:

..........

The OP has a cam pin area wear problem as stated in the first post, and you jump in and take over the thread with a rear reciever wear/rear carrier picture expo that has nothing to do with the original problem. I made the suggestion of creating a seperate thread because your problem is very interesting and would be easier to keep track of . Now i could care less about it , lets get back to helping the OP with his problem.

Cam pin wear is normal for all AR's. It is exasperated by piston guns do to the different operation but it is basically a result of the cam pin not being fully aligned behind the gas key or piston strke face.. In a DI gun, gases inside the bolt carrier, pushing against the ring seals, thrust the bolt forward out of the BCG. This usually assures the bolt is fully extended before the BCG unlocks and starts its travel to the rear. In a piston gun, the BCG is being pushed back. The only think keeping it unlocking is the lugs. Once the bolt has rotated and is free of the lugs, the BCG is free to move rearward. The cam pin may or may not have reached its full travel, aligned behind the piston "gas" key. It gouges into the upper, shaving the metal off you see stuck to the BCG. The good news is it will not continue to wear once it gouges out enough clearance where the cam pin sits when the bolt lugs free from the chamber lugs.

There are two things you can add to lessen the effect: First, a POF Roller Cam Pin which is round instead of square and rolls onto the portion of the upper where it would normally take chunks out. It will still wear this area, but not near as bad. Second is the Adams Arms spring if it isn't already installed. This mimics the action in a DI gun, pushing the bolt out of the front of the carrier and aligning the cam pin as it is releasing. I do both.

Roller Cam Pin

Now to address the hijacker. What you are experiencing is carrier tilt. This is also common in piston guns due to the off axis forces on by the op rod on the BCG. The "ski's" are there to minimize the effects of this, not hurt more. Some manufacturers add extra bearing surface at the front of the BCG to tighten up the tolerance a bit in the upper and minimize the play that can contribute to more tilt. While this will wear into the upper, typically where the buffer tube inserts into the upper, I have never seen it produce shavings like the Cam Pin gouge will. It tends to be more gradual and WEARS into the bottom rear of the upper so I think you may be exaggerating a bit. Curiously, my Barrett Rec7 has zero carrier tilt although the piston system is similar to my other piston AR's. It does, however, have slight wear in the cam pin area.

Can you post some pics?