You list is odd to me. When I think of benchrest I don't think of any of the choice you have save one. There is a 22 lr benchrest circuit. but for centerfire none of the choices are common. Your list would have been more reasonable if you included: 6 PPC, 6 BR, 22 PPC, 22 BR, 6.5-284, 222, 30 BR etc. etc. Those are more logical choices for BR competition. Of those choice I would have to say either 6BR or 6.5-284 as I own one of each.