Came back from range after testing new handguard and gas block, everything functioned correctly, I did try-out for the first time a box of 180 grain Federal Power-Shok that had recoil for days .. got back and observed this shiny big nick/chip on the upper receiver like a piece of metal was chipped away. All other components look ok..bolt, handle, etc. it looks like it may have been caused by the charging handle violently returning and hitting that edge. Should I be concerned about rust since its exposed metal and what could have caused this?
Hate to send it back to S&W and wait a year on new receiver.