Is this the first time you've fired the rifle or was it shooting better before? Not being very adept at adjusting these things myself, I'd send it to someone like Champlin or G&H to have it regulated. I haven't done that before, but that would be my instinct. Shooting 12 inches high is no good. Like having a bent putter that requires you to play for 12 inches of break on a straight putt. With that as a starting point, it's hard to do anything accurately, and it really gets ugly with putts that aren't straight.