Well both out at 100 yards have shed a lot of velocity and are pretty close. The price difference, including lowering the level of powder between the two calibers, is it's about .32 cents per shot for me and my rifle using store bought round ball in a .54. It's about .25 cents a shot for me if I was using a .50. So you save $7 for every hundred rounds with a .50 and store bought ammo. (I lower my costs with casting my own, to a mere .22 per shot) So for every 200 rounds you save enough to buy a pound of powder from Graf's & Sons.
LD
LD