That’s one of the things the rules aren’t clear about. Of course, you could switch to skeet or trap and shoot lead by the ounce instead of by the grain. Apparently, that’s OK for condors. Go figure.
I reload black powder pistol and rifle cartridges,but I don’t know anyone who manufactures or reloads black powder rimfire cartridges, like the old late 19th Century .22 and .32 rimfire rounds.