An AR-15 accessory often overlooked is the M9 Bayonet. The M9, with its 7-inch blade, when mounted is used by the military as a show of force weapon used to deescalate and deter violence. The M9 is the military's current USGI bayonet for the M16 Rifle, M4 Carbine, and the Mossberg 590 Special Purpose Shotgun. The M9 was adopted by the US military in 1984 as the official replacement for the M7 Bayonet. Both bayonets are pictured for comparison purposes. The M9 bayonet is issued with a sheath designed to double as a wire cutter. The M9 pictured is manufactured by Ontario Knife Company in New York and was purchased for $95 (see Amazon Store page for more details). The pictured M7 was purchased for $35. Based on your budget either bayonet is a great addition to your kit as a fighting knife.