My accuracy load is 28.3 gr of 748 using ww brass and federal match primers pushing a 50 gr ballistic tip or vmax, both shoot to the same point of impact. Haven't chronied the load yet but the vmax wound channels have been just plain devestation on groundhogs, haven't shot one with the ballistic tip yet. I have a lb of benchmark and 3031 that I'm going try when the weather turns nice. What I did was to weigh a powder charge to the bottom of the case neck on both a 223 and 223 AI case, came up with a 10% difference in case volume and adjusted my starting load up 10%. I'd suggest doing this calculation with cases formed in your chamber after being full length sized. If you err do so on the side of caution.