A std. mag. action could be converted to 26 Nosler without going full mag length. The 26 Nosler should fit a 7RM, .300WM etc. std length mag. action.
Here is a photo of a .300 RUM action converted to .404J, the parent round. See the "windows" in the box, allowing the wider bodied rounds to properly fit under the action rails. Even though this is a full mag. length RUM action, the same idea should work. This is a M-70 RUM action, I haven't examined a M-700 RUM action but would think it has a similar arrangement.
One could cut these windows in a std. mag. box and alter the follower for the fatter round. I've heard that the std. mag. follower sometimes works OK with these fatter rounds without alteration.
DF
http://www.24hourcampfire.com/ubbthreads/ubbthreads.php/topics/7846376/2
