Purchased a flat top about two weeks ago. Finally got a scope mounted low and put 40 rds through it. Shot near perfect. Everything was a little left but that could have been: 1) Scope mounted to low, making it awkward to get a good sight picture with hearing protection. 2) Shot standing unsupported 3) Just no longer used to shooting an AR15/M4 Range was busy so could not do a proper sight in. May have to get a bore site and definitely taller scope rings.