I had trouble with a new pistol upper not ejecting the shell and put it aside until i could get home and check it out. Got home and cleaned all the guns i brought to shoot and took the upper apart. It came out in three pieces, the charging handle, the BCG, and the top of the BCG yes i mean the part with the staked allen screws. the head of one of the screws was missing and the other was sheared off mid length. I attached pics to show what happened,anyone had this mishap?