I have a new scope on an AR15...can't afford the luxury of burning ammo to sight it in....I have a magnetic laser sight from Wheeler Engineering but if it is not perfectly centered on the barrel crown there is a big error at 50 yards- and, in any sun I can't see the laser. Not my best purchase to be sure. Any suggestions? I see them at Midway for <$30....burn that pretty quickly at today's ammo prices. Thanks in advance. Ned