BM 16" HBAR.  Functions flawlessly on XM193/Q3131A/Wolf.  About 1000 rounds through it so far.  

Problem: I have noticed a moderate wear spot on the inside of the upper.  The spot is oppsite the ejection port, just behind a cut-out I assume is for the cam pin to function, just below the channel that the charging handle functions through.  The bolt carrier/base of the gas key/cam pin also seem to have some wear on them where they would possibly rub this area.  I would describe the wear as a little more than peening.  

Is this regular break in?  

Normal

Thanks