Mk 19

The Mk 19 is an American 40 mm belt-fed automatic grenade launcher developed during the Vietnam War. Development began in 1963 with the hand-cranked Mk 18 multiple grenade launcher; the need for more firepower produced the self-powered Mk 19 Mod 0 in 1966, which proved neither reliable nor safe enough for service. Improvements from 1971 gave the Mod 1, of which only six were built but which performed well on Navy riverine patrol craft, and the Navy's Mod 2 of 1973 improved reliability, safety and maintainability. A complete redesign produced the Mk 19 Mod 3, adopted by the Army in 1983 and still the definitive version. General Dynamics Ordnance and Tactical Systems has built close to 35,000 Mod 3 systems for roughly thirty customers since 1984.

The launcher is blowback operated, air cooled, crew served and fires from an open bolt, designed specifically not to cook off. Cyclic rate is 325 to 375 rounds per minute, giving a practical 60 rounds per minute rapid and 40 sustained. Maximum range is 2,212 m, with an effective point-target range of about 1,500 m - the limit to which the rear leaf sight is graduated. The minimum safe distance is 310 m in training and 75 m in combat. Rounds are fed mechanically onto the bolt face by pulling the charging handles; pressing the trigger closes the bolt and releases the firing pin, and recoil blows the bolt back, feeding the next round while pushing the spent case off the bolt face. Ammunition comes in cans holding 32- or 48-grenade belts weighing 19 and 27 kg respectively.

The primary round is the M430 high-explosive dual-purpose grenade, which kills within 5 m of impact, wounds within 15 m and penetrates 5 cm of rolled homogeneous armour on a direct hit - enough to defeat most infantry fighting vehicles and armoured personnel carriers. Its 40x53mm ammunition is not interchangeable with the 40x46mm rounds of the M203, which develop lower chamber pressure and correspondingly less velocity and range. At 35.2 kg the weapon alone is heavy enough that vehicle mounting is preferred to the tripod, and its low recoil and comparatively light weight for its effect have seen it fitted to attack boats, Humvees, AAVs, Strykers and a wide range of naval mounts. General Dynamics agreed with Singapore Technologies Kinetics in November 2014 to produce 40 mm high-velocity airburst ammunition using a programmable time fuse, which is compatible with the Mk 19 and improves its effect against concealed and defiladed targets.

Beyond widespread US service, the Mk 19 is used by Australia, Poland, Portugal, Spain, Sweden (as the Grsp 92), Taiwan, Thailand, Ukraine, Argentine and Brazilian marines, the Chilean Army and Marines, Iraqi special forces, Kosovo, Lebanon, Malaysia, Mexico, Moldova, Morocco, Pakistan and Saudi Arabia. Egypt manufactures it locally at Helwan and Turkey under licence at MKEK. Israel adopted it as the Maklar and formerly produced it domestically, and Japan mounts it on the AAV7 vehicles of its Amphibious Rapid Deployment Brigade. Aselsan's Şahin counter-UAS system, in Turkish service since July 2022, is built around the Mk 19 firing Atom 40 mm ammunition against mini and micro drones out to 700 m.