Cartridge style laser boresighter fits:.223(5.56x45 NATO)/7mm/7.62x39mm/12gauge/20gauge/30-30WIN/.30-06Springfield/50BMG/.308WIN/300WIN/8x57mm/9.3x62mm/7.62x54R/.303ACCURATE bore sight will have you sighted in fast while saving ammunition,constructed of high grade aircraft aluminum designed to slide into the chamber of your firearm easily,a straight laser beam projects down the middle of the bore for a precise trajectory,3 AG3 batteries included,<5mW

Chamber laser boresighter 7.62x39mm