I saw an AK-47 while in Vietnam and it had a 30 round magazine. So I cut the top and bottom off of a couple of M-14 Magazines and welded them together and made a "40" Round magazine for my M-14. It really didn't work very well when test firing it, several of the last rounds would not chamber with only two springs. So I put "three" springs into the magazine, but then I could only load a little over 30 rounds. There just wasn't enough room for three springs and 40 Full Metal Jacket rounds in that magazine. I sure received some strange looks while walking around with my 40 round magazine.