92 magazines go from double column to single column. Virtually all modern submachineguns feed from a double column at the top. Also, the 92 magazines are slanted while the full double column magazines are not. Like all pistol magazines, the 92 magazines are just not an efficient use of space when compared to typical submachinegun magazines. I am surprised that they have not seemed to curve the magazine a bit as they're typically more reliable in 9mm when designed that way.