What cartridge is standard for the M9 Pistol?

The standard cartridge for the M9 pistol is the M882. This cartridge is a 9mm NATO round, which is specifically designed to meet the performance requirements for the M9 service pistol used by various branches of the U.S. military. The M882 cartridge is recognized for its reliability, accuracy, and lethality in combat situations, making it the official choice for use with the M9 platform.

In contrast, other choices do not correspond to the correct caliber or are associated with different firearms. The M9A1 is an upgraded variant of the M9 but does not refer to a specific cartridge; the M80 is a full-metal jacketed round primarily used in 7.62mm NATO rifles, while the M1911 references a different firearm altogether, which typically uses the .45 ACP cartridge. Thus, the M882 remains the definitive cartridge for the M9 pistol.