So not to highjack the 450 Bushmaster thread.
This was one of those "what if" things while waiting for some parts to show up. I was looking for ease of making brass and something that wasn't proprietary to a maker. I wouldn't want to spend 30 minutes per case to have the AK punt it to China or dent the crap out of it. Or send a barrel to someone to cut a chamber for X2-X3 times the cost of what a reamer would be and I could cut it myself. So, a 30.06 case cut below the shoulder, some 44 mag bullets that were on hand, and you get something like this.
The case would have to be fire formed as you can see from the pic that there is a dip below the seated bullet. The lead on top of it was smashed in the loading due to not having a 44mag seating die at the time. The case has not been crimped. On the 44automag they inside neck reamed to a depth of .590 which might be needed to help keep the bullet from moving under recoil...don't know. A Lee factory crimp might keep it in place or might need a canalure in the case....don't know. A RCBS 44mag neck sizer is too big to start in the case, so an expander cone is needed.
To answer some of 1bigguns questions.
The left one is a standard 44mag, the center is the 44???, and of course a 7.62x39. I don't know why in the pic the case looks like it was cut with a hacksaw, it wasn't. The length is 1.700 inch. Don't remember why that length as you can almost get a 2 inch case by cutting a 30.06 at the shoulder. Maybe it was to use a standard die, but the 444 would be the only thing close or maybe it was close in case volume to another conversion cartridge to have a starting point for loading. Before setting a length I would want to get some 180 to 300 grain bullets to see what the OAL would be. It was just one of those lets see thing.