I certainly do not want to rain on your parade but IMO boresighters are a waste of money. Start at 25 yards and use a pc of plywood big enough to frame your target. Shoot 3 shots to confirm it is not your shooting formthen make the necessary scope or open sight adjustment to get on paper. I usually hit paper on the first try and adjust. Then move out to 100 yards and repeat.A bolt action is easiest as you justremove the bolt and center the target as best as you can through the pipe with your naked eye.