I use Brennekes to get close like you do but if i isght in 2in low and 2in to the left im dead on with the Federal Barnes Expander slugs i shoot to hunt with. Ive tested this multipul times over the last 2 years and its always there. I still always shoot the slugs im hunting with just to be sure but it saves alot of money in my pocket doin it this way since i cant just got shoot 6 or 7 rounds to sight in.