300 WIN MAG Brass Red Laser Bore Sight. Caliber-specific brass bore sight built exclusively for 300 Win Mag barrels, made of solid premium brass for tight, stable barrel fit. Equipped with a 635-655nm visible red laser under safe 5mW output, delivering clear aiming dot from 15 to 100 yards with a 1.5-inch dot at 100 yards for easy optic alignment. 73g solid brass cartridge design inserts smoothly into barrels, enabling quick pre-zero calibration to save ammunition during hunting and range shooting.