Sizing the round balls works, but it can be a PITA to get the "shank" aligned in the brass. The longer the flat, the better. I've gotten fewer fliers with the balls that were just oversized and crammed into the case mouth. I've done .457 balls in a 45 Colt rifle and pistol. The rifle had a big enough chamber that I could just seat the ball into a very belled case without sizing. I used those same balls sized to .432 in a 44 mag, and they shot straight to longer distance, but with fliers every so often. The plain balls around the same .432" shot more consistently. In various 22 cals from 22 Hornet and 218 Bee to a 22-250, I had good luck with some version of buckshot sized to .225". I did some .244" sized buckshot in 243 Win as well but those did not work out well. Various 30 cals were successful with .311" buckshot, from 30-30 to 30-06.
Over all, fun for plinking, and well worth the experimenting time. Other than the 243, all results were generally satisfactory at 50 yds, and some to 75 yds. I never solved the 7mm ball conundrum, and have never done any round ball tests in 35 cal. Just never found the right mould or shot for either.
