Looking to get a barrel to add onto my SSK 375 JDJ. I'm thinking 224 or 6mm flat base bullet out of a case about the size of a 223 or slightly bigger. The ones I know are: 219 Donaldson Wasp 6mm Donaldson Wasp 6x47 Lapua 6mm TCU Are there other good ones? Who should make the barrel? This is meant to be a 100, 300 benchrest pistol and maybe groundhog out to 500 yards.