Ncstar cartridge red laser bore sighter set - NcStar Cartridge Red Laser Bore Sighter Set / .223, .308., 30-06, 7mm

Since they are adjustable, you can get on paper with these, and when you are zeroed in, put the laser back in and adjust it to the gun to get near zero the next time you use it on another gun. Really helps with scope setup after initial mounting.
Pros: Cartridge style lasers match the chamber and bore well and can be inserted or extracted easily. Comes with batteries and ready to use. Lasers are adjustable if you dare.
Cons: Not dead on accurate, but is only supposed to get you on paper. One unit kept fading as new.

This review was written in the old system and had content requirements that are different than reviews written today.