Bore sighters are a waste of money, unless you mount and boresight scopes for a living or you like guns that you cannot remove the bolt from and see through the barrel from the breach (many semi-autos, for example). For bolt action rifles, muzzleloaders with breach plugs, single shots, etc..., you're better off saving your money and just using your eye. Just take out the bolt or breechplug or open the action, mount the rifle in a solid vise or rest, and look through the bore keeping it centered like a peep sight while you adjust the rifle so the center of the target at 25 yards in dead center in your view. Then, without disturbing the rifle, move the turrets so the crosshairs are also centered on the 25 yard target. Double check your work, and get it as close as possible, then reassemble, load and fire. You should be easily able to get your shot onto an 8.5 x 11" sheet of paper at 25 yards. The last rifle I mounted a scope to I used the eyeball method and was within 2" of dead center at 25 yards. That's as good or better than most boresighters, and it didn't cost me a dime. It took 2 shots to have the rifle ready to shoot at 100 yards, and the third shot ever from the rifle was 1.5" from dead center at 100 yards.

Mike