I saw that you had posted that in the 44??? thread. wasnt trying to miss speak for you. LOL. I came up with my length by fitting the bullet and case to the mag.The reason I cut it at 1.700 is that is the length that the 44 Ballard Extra Long is cut at before opening it up. It's based on the .220 Swift, but should be close enough to get a safe starting load. Plus it left some OAL room for different bullets in the AK mag.
I want to try to blow some 7.62x39 cases straight and see if you can in fact load a 41bullet into one. this would require no bolt mods might be able to use a 41 mag die to size at least part of it but would likely require a custom die. how ever it could likely be made from a die blank on a lathe as it is a straight case. HMMM