I have a M1A bush rifle which shot great with original folding stock & birch stock. I was tempted by a beautiful brown laminate stock, so I bought it & had the gun store owner (service rifle is his specialty) fit it. My M1A now shoots 18' high when cranked all the way down @100 yds. Did the guy mount it with pressure on the barrel or what? If I get the higher standard M1A front post, won't my rear sight range be off? Any other way to solve it? Help- I'm out of my depth.