I am puzzled, I thought that the scope as it was attached to the barrel should maintain some reasonable zero on dissasembly and reassembly. The gun I had was a puzzle, it went back to Benelli once and they provided a new index point for the internal nut. This did not help. I am willing to try one again as I love the engineering design, I would just hope that they would have found the bugs and fixed them. I don't dissasemble my bolt guns as they can be cleaned from the breach. I normally do not clean them period other than to wipe with oil both external and internal after the season. I admit that the Benelli I took apart and cleaned each time I shot it. I probably should not have, but it was in my opinion inconsistent.