blhof+1 I had a problem with the first B-Square mount I bought. The tabs that slide under the vent were just a tad to big. Didn't take but 1/2 hour with a fine file and stone, and got them to slip right under and a nice fit. Second mount was a used one at a gun show, and went in. Still have them both. Now that I'm getting older, plan is that the next deer hunting trip will put a red dot on, as the eye's arn't what they use to be. gypsyman