.257 Roberts AI
Hello everyone, I'm new here. I usually spend time on the G&A forum. But I was out surfing and saw some interesting posts from here so I stopped by and registered. Anyway, below is my comment on the .257 Bob and it's derivative, the .257 AI.
I saw a thread on this subject that may be old now. But the comments were about magazine length for this cartridge and the fact that you have to worry about it when seating bullets out far enough that they don't pertrude too far into the powder space limiting your load. If you're looking to build either one of these and you don't want a really long action, get a Yugo Mauser. It's .25 inch shorter than a standard 98 (if there IS such a thing as a standard 98) and the magazine is almost long enough to fit 06 length cases in it. In fact it is done with a minor midification. But this is a medium length cartridge and the Yugo is the perfect doner for this project. How do I know? Because I just finished a project, or rather my gun smith did. Even seating longer 117 grain bullet in it gives plenty of room in the magazine.
Also, I've heard that the .257 caliber needs a 1-9 twist to stabilize the longer heavier bullets. I don't know what their definition of longer heavier is, but I've never had a problem. And though I personally don't have a 25-06, I know a bunch that do and theirs is almost to the man a 1-10 twist and they have no problem stabilizing even 120 grain Spitzers. Maybe it's a gun by gun deal, but I haven't found the one that won't stabilize even the 120s. Does anyone else have any experience with this?
I have three Roberts and recently parted with an AI. All of them were 1:10 and all stabilize 120's, and even the old 125 grain Barnes. Sounds to me like you were reading keyboard ballistics.