RE: Sighting in a pistol
Sounds to me like something is bent or possibly broken. Have you taken it appart to inspect all the parts? If you can't see anything obvious, you may want to check everything with a straight edge to see if something has a slight bend in it. If you can't find anything you should take it to a gun smith to have it checked by a pro before you shoot it any more. IMHO, it's not worth the risk.