Chip - yes, that is certainly where the .250 AI gets most of its increased powder capacity. I like this cartridge because you can use both standard and wildcat ammunition. And, when you use standard ammunition, your fired cases are perfectly formed. I have quite a bit of experience with the .257 Robert AI. I currently have an 8mm-06 improved and used to have an 8 mm Gibbs which is basically and 8mm-06 improved improved. I also had a .280 AI/.270 Gibbs switch barrel that I liked real well. It's all fun
