Just ordered a 10 FCP-K in 223. I plan to put a Sightron SIII 6x24x50 on it. This scope has 100 MOA adjustment per the manufactures data. If my thinking is correct, since the scope is some number higher than the bore, I already have some elevation built in (more than 50 moa) I'd think. This is going to be my effort to shoot prairie dogs and cans at 300 to 500 yards. My specific question is: Do I need an additional 20 MOA built into the base? If I'm shooting farther than 500, I'll use the 6mm. Your thoughts and experience?