Hello. I recently purchased a newengland handi rifle chambered in 22-250. The gun groups ok at 100 yards but at 200 it is way off. The scope that is on it, came already boresighted. I had no problem getting it on paper at 100 yards. I am shooting winchester 55 grain powerpoints. My question is, what can I do to make this gun more accurate? I am no gun smith but I know a good one. Thanks!!