I just picked up a Millet 6-25x56mm AO Scope 30mm tube, and I like it a lot. It is not a Leopold but then again I got a great buy on it. I have it on a 700BDL in 6mm but I am thinking of putting it on a Double Star 24" SS HBB A3 upper I picked up last show. I was thinking of using the Weaver style rings and since there is no front sight, I wouldn't need a QD style ring. I was wondering if you could get a 56mm Objective lens on a AR flattop w/o a riser? But then again, I have a 30mm set of Leopold style rings and I was wondering if there was a leopold base for a flattop AR so I could re-use the rings I have?