LEE 575 round ball load: 1 compact gas seal + 1/8" 28 ga mini nitro to fill the top of the gas seal + 1/4" fiber wad + 1 BPI commander with 1/8" 28ga nitro card to seal the gas base + 1/4" 28ga felt wad in the wad cup + .575 lee RB + roll crimp over 18gr Pro Reach.
I only loaded 3 and shot them at 25 yards off my bipod. Two balls went into one hole and the third clover leafed by half it's diameter into the first hole. I had this target hardbacked by butcher paper and then 1/8" cardboard so I Did Confirm the 2 ball one hole shot lapped in the hard board by about 1/16".
This load fit Perfectly in the Commander Wad (020TC20). It could not have been a better fit. I am going to load a couple of dozen of these and see how they fly at 50 and maybe even 75. I wish I had built more. The recoil was about like a .243 (maybe less).
rch