When I was out of work I sold a lot of my optics and a few rifles off. Among the casualties were my AR-10 and two 5.56 ACOGS. I still have my .308 ACOG, but unless I mount it on my FAL which I would more likely scope, it really has no home and I don't plan on buying another .308 unless it is the new XCR. Meanwhile, how far off would the BDC be if used on a 16 inch barreled 6.8 or 5.56 AR? I know I can zero the chevron for a set range such as 200 yards and it will be fine on either rifle, but if I wanted to calculate drop how much variance would there be with say 110 grain 6.8 or 62 grain 5.56 as opposed to 150 grain .308?