(619 grain), and M962 SLAP-T. The latter ammunition along with the M903 SLAP (Saboted Light Armor Penetrator) round can perforate of FHA (face-hardened steel plate) at , at , and at . This is achieved by using a tungsten penetrator. The SLAP-T adds a tracer charge to the base of the ammunition. This ammunition was type classified in 1993. When firing blanks, a large blank-firing adapter (BFA) of a special type must be used to allow the recoil-operated action to cycle. This functions on the principle of a recoil booster, to increase the recoil force acting on the short recoil action. This is the exact antithesis of a muzzle brake. Without this adaptor, the reduced-charge blank cartridge would develop too little recoil to cycle the action fully. The adapter is very distinctive, attaching to the muzzle with three rods extending back to the base. The BFA can often be seen on M2s during peacetime operations. Deployment The M2 .50 Browning machine gun has been used for various roles: A medium infantry support weapon As a light anti-aircraft (AA) gun in some ships; up to six M2 guns could be mounted on the same turret. As an anti-aircraft gun on the ground. The original water-cooled version of the M2 was used on a tall AA tripod or vehicle-mounted anti-aircraft weapon on a sturdy pedestal mount. In later variants, twin and quadruple M2HB Brownings were used, such as the M45 Quadmount (aka "meat chopper") used on the US M16 half-track carrier. Twin or quad-mount .50 M2 guns normally used alternating left-hand and right-hand feed. Primary or secondary weapon on an armored fighting vehicle. Primary or secondary weapon on a naval patrol boat. Spotting for the primary weapon on some armored fighting vehicles. Secondary weapon for anti-boat defense on large naval vessels (corvettes, frigates, destroyers, cruisers, etc.). Coaxial gun or independent mounting in some tanks, including but not limited to: the M47 Patton, M48 Patton, M4 Sherman, M24 Chaffee, Heavy tank M6, Heavy Tank T29, M1 Abrams, M60 Patton, M46 Patton, and the M26 Pershing. Fixed-mounted forward-firing primary aircraft armament (AN/M2 and AN/M3 light-barrel versions only). The AN/M2 was used as primary armament in almost all World War II U.S. pursuit aircraft (such as the North American P-51 Mustang, Republic P-47 Thunderbolt, Lockheed P-38 Lightning, Bell P-39 Airacobra, Curtiss P-40 Warhawk, Grumman F6F Hellcat, and Vought F4U Corsair). It was also used in