Do you have more information on the cartridge dimensions? I have a set of .350 Ackley Magnum dies sitting here doing nothing. I have no idea if they are close or not.
Oh My! They are quite close - The link is to an image showing dimensions for the three .350/.358 magnums being discussed - Mashburn, Ackley and Norma. Biggest difference is in the how "tall" the soulder is - appears Art Mashburn was a believer in REALLY SHORT Shoulders! Guess that is what Fire-Forming is for if you can figure out how to get it inside the chamber of the rifle!
FINALLY - figured out posting of pics!
35 Magnum - Mashburn Ackley Norma - Dimensions by
Mike, on Flickr