The noticeable outward curve on some Glock pistol magazines, particularly those chambered for the 10mm Auto cartridge, results from the cartridge’s relatively large dimensions. This increased capacity magazine often presents a more pronounced profile compared to magazines designed for smaller calibers like 9mm. A visual comparison between a Glock 20 (10mm) and a Glock 17 (9mm) magazine readily illustrates this difference.
This characteristic is a direct consequence of designing a magazine to hold a powerful cartridge within the constraints of a reasonably sized grip. While some find the increased profile less aesthetically pleasing or less concealable, it is a necessary trade-off for the increased ballistic performance offered by the 10mm Auto round. The cartridge’s popularity among those seeking greater stopping power, particularly in hunting and outdoors applications, has cemented its place in the market despite this design consideration.