Can anyone tell me if a Kimber .308 Win. has the same magazine box as the .257 Roberts? I am trying to determine if a ..308 could be rebarreled to a .257 and feed without modification of the mag box. Would a Sako .308 magazine feed a .257 Roberts? I am talking about the standard short loading of a .257 Roberts with approx. OAL of 2.8" which would fit in either magazine - just a question of would it feed properly.

Looking at my .308 Kimber, it seems small, but I am sure its only a matter of replacing the follower or perhaps opening the existing box up a tad...

I'm sure it can be done..The 257 case is mostly larger than the .308....If its a problem and any gunsmith with a caliper can tell you, or better yet you could try a few 257s in your 308 and see if they will start into the chamber, they won't fit but will tell you if they will feed. If not then make a 257/308 that's a great wildcat and brass is more readily available than 257 brass for sure!!

Actually the body of a .308 is larger than a .257. the measurement at the shoulder of the .257 is smaller than the .308 - .429 vs .454. That's why a 6mm Rem. rechamber won't clean up a .243 chamber. The .257 case is just longer - 1.727 in. to the shoulder on the .257 and 1.556 on the .308, but OAL length is the same. That's why I thought it should feed.