CP may want to take a stick and beat me around the head and shoulders for this answer, but here goes. Figure out the volume of BP it takes to load you bullet to the depth you want and give the powder a very light crush. When loading my Colt 1860 Army copy I never measure the powder, just leave the chamber down about half the diameter of the ball then crush it seating the ball. You don't want to crowd the .45 Colt that much though - say no more than a 1/16 inch crush.