AK-47 rifles can use both 5.56 and 7.62 mm cartridges, but they are more commonly chambered for 7.62x39 mm. Key differences between 5.56 and 7.62 mm: - Velocity: 5.56 mm rounds are faster, with a typical muzzle velocity of around 3,000 FPS, compared to 7.62 mm at about 2,500 FPS. - Recoil: 7.62 mm rounds generate more recoil, which can affect the controllability of the weapon. - Stopping power: 7.62 mm rounds have greater muzzle energy and better penetration, making them more effective at longer ranges and for hunting larger game. - Accuracy: 5.56 mm rounds are considered more accurate, especially over longer distances. Ultimately, the choice between 5.56 and 7.62 mm depends on the specific application and personal preferences.