.257 Roberts

[Catfish]

I load for a .257 AI with a 1 in 12 twist and it will still group pretty good with the Serria 117 gn. bullets. I built it for a varmint rifle, but did lone it to a friend to hunt antlope with. He fire 1 shot at an antlope, the guide he had said it was 450 yrds., it fell over dead and the hunt was over. With the 1 in. 10 twist I would guess you would get better groupes with the 117 gn. bullets.