I've never used one. What i do is pop out the bolt and sight down the barrel with the rifle locked in a wood vice work table and set the sights, or scope to an object sighted looking through the barrel. saves time and money. that should get you on paper. but if i were to get one i woud get one of those lazers that fits in the chamber. cabellas has them as well as all the other on line stores. cost about 50dollars. good luck.