I have the Laserlyte bore sight from Wal/Mart. $39.95. I've sighted in numerous guns with this sight, it's done a GREAT job. Fits .22 to .50 caliber. Battery life is very good, I'm on my 1st set of replacement batteries - (LR44,AG13 ,or A76 batteries. Three required. It will run for better than an hour before battery replacement is required. About $2.00 to replace. It will do iron sights, red dot scopes or regular crosshair scopes.