Looks like you almost always seem to get a "wayward" shot there old boy! I'd say that right now that rifle shouldn't be shot at any game beyond 75 yards for sure. But I think you'll figure something out for it.
I think I'd try a different lube and a thinner patch with your .575" balls. The ones you gave me shot really well out of my .58 GM barrel. So much so that I got myself a .575" Lee mold and cast a bunch.
As far as Lube goes I've been having some really good results using Jon's Anti-rust lube. I don't know what he puts in it but it is super slick and makes for nice loading.