magazine shape

[chexmix]

Is there a benefit to having a curved magazine? The AR and (more so) the AK have curved magazines. These magazines don't protrude below the gun as far but is there another benefit, does it feed better?

 

[5.56RifleGuy]

With the shape of the cartridge cases, the magazines need to be curved to provide reliable feeding. They would bind up in the mag otherwise. You wont see the same problem with cases that have little to no change in the cartridge shape. That's why when you see something like a 9mm hand gun or a subgun mag, they are straight a lot of the time. Sometimes you will see a curve on the higher capacity ones though.

 

[mete]

Compare the case dimensions of a 9mm and 45acp .The 45 has very little taper while the 9mm has substantial taper.When you stack up 20-30 cases you'll note that the 9mm stack is curved and the 45 stack is straight.
It does make a difference in reliability.In fact the original H&K 9mm had a straight magazine and the feeding wasn't reliable .When they changed it to a curved magazine reliability problems disappeared !!