I have found that the 7.62X39 cartridge is a good cast boolit round in my AR 15 rifles. Mine have the standard bore/groove of .302/310 and 1 in10" twist. I am loading 25 grains of IMR 3031 and the Lee .310/125 boolit with gas check and lubed with LBT blue. I am casting with WDWW and get BHN 22. Groups average 2.5 inches at 50 yards and about 4 inches at 100 yards. I get zero leading and accuracy is as good or better than condomised bullets at 2200 fps.
Any one out there with other cast boolit formulas that give good results?