Instead of buying .530 balls for a .54, buy a mold and make your own...I haven't bought a round ball in over 30 years...I use a .40 and a .54...Within a few hours, I have enough to shoot all year...

I have Rapine bag molds for both but have recently added a .530 Lee mold, for only $18...Semisane posted about this mold on sale last month, so I snapped one up...