AR-15 base weapons (M16, M4) are much more accurate. So there's an advantage at distance. Also it uses smaller, faster rounds that have less stopping power, but

AR-15 base weapons (M16, M4) are much more accurate. So there's an advantage at distance. Also it uses smaller, faster rounds that have less stopping power, but are easier to carry. So there's a greater chance of running out of ammo with an AK-47.