The 722 is still a short action, and the 257 AI is simply an improved version of the 257 Roberts, allowing for more powder capacity, etc. P.O. Ackley was well known for his designs that removed some of the taper of a round, added a sharper shoulder, and enhanced it's performance. Yes, you do have to reload for it, as there is no factory ammo on the shelf. Dies and data are readily available.