STANAG 4090 defines 9mm NATO as having a bullet weight of 108 gr to 128 gr inclusive. Muzzle energy from a standard proof barrel must be at least 400 ft/lbs and not more than 600 ft/lbs. There is no standard for velocity.

There are detailed dimensions for the case and chamber to insure that all NATO ammunition will function in any NATO firearm. Standards for maximum pressure, accuracy, and penetration of body armor are also specified.