I'm shooting an 18" gas gun with a BDC reticle.
My primary load is IMI 77gr @ 2710fps. I zero it at 63 yards in order to match my BDC.
My training load is PMC XTAC @ 3120fps. I zero it at 100 yards in order to match my BDC.
If both loads were zeroed at same distance, I could just measure the...