Ordnance Notes -- by Bob Stoner GMCM (SW) Ret.

Mk 19 Mod 0 40mm Automatic Grenade Launcher

The Mk 19 40mm grenade launcher is now standard issue with the U.S. armed forces.  Development of the Mk 19 Mod 0 began in 1963 by Naval Ordnance Station, Louisville, KY.  It was adopted for service by the Navy in 1966.  The Mk 19 was designed to fire the M383 HE grenade projectile that was used by the Army’s helicopter-borne M5 machine gun system used on the UH-1 helicopter.

A good shot of a Mk 19 Mod 0 40mm grenade launcher installed aboard Tango boat T-131-1 during the Viet Nam War. The gun is shown with its feed cover open and belted ammunition in the feed position. This gun has double cocking handles. The trigger is the T-shaped object between the spade grips. The “peace” sticker on the gun shield is a sailor’s tongue-in-cheek jab at the peace activists in the USA at the time. (Photo: Larry Kennedy)

The Mk 19 Mod 0 had problems during its Viet Nam War deployment and after a product improvement program from 1971 to 1972, six units were deployed with naval riverine forces as the Mk 19 Mod 1.  User improvements resulted in the Mk 19 Mod 2 being fielded in 1973.  More user improvements resulted in a complete redesign of the Mk 19 during the years 1973 to 1976.  The definitive Mk 19 Mod 3 was released for service in 1976.  The Mk 19 Mod 3 was adopted by the USMC in 1982 and by the U.S. Army in 1983.  The Mk 19 is a blowback operated and air-cooled.  Its receiver resembles a shortened version of a .50 Browning machine gun without the barrel support and a short, stubby barrel.

The Mk 19 fires 60 rounds per minute in rapid fire and has a 325 to 375 rounds per minute cyclic rate.  Its maximum range is 2,200 meters (2,405 yards) and a maximum effective range of 1,550 meters (1,695 yards).  Muzzle velocity of the grenade is 790 feet per second.  Overall length is 41.5 inches (Mk 19 Mod 3). 

Weight is 72.5 pounds (Mk 19 Mod 3), without mount.

The high-explosive, dual-purpose (HEDP) M430 or M430A1 grenade can penetrate up to 2 inches of armor.  The grenade has a kill radius of 5 meters (16.5 feet) and wounding radius of 15 meters (50 feet).  Grenade arming distance is 15 to 30 meters (50 to 110 feet).

WARNING:  The 40x53mmSR grenades used by the Mk 19 and the 40x46mmSR grenades used by the M79 and M203 grenade launchers are NOT the same.  Grenades for the latter two launchers develop much lower pressures than those fired by the Mk 19.  The M79/M203 grenade launcher barrel is aluminum, while that of the Mk 19 is steel.  The Mk 19 grenade round is longer than those used by the M79 and M203 launchers.  Attempts to fire the Mk 19 grenade round in the M79 and M203 launcher will destroy the weapon and damage or kill the operator.

Ammunition types are:  M430 or M430A1 HEDP; M383 HE; M385 or M918 TP (target practice); M922 or M922A1 dummy rounds.  Links: steel, disintegrating M16A1 or M16A2.  HEDP, HE, and TP ammunition is pre-linked in M548 boxes with 48-round lengths. The Mk 19 is a very significant boost to the firepower of a special warfare unit.

A left side view of a Mk 19 Mod 3 40mm machine gun. The only apparent difference from the Mk 19 Mod 0 is the addition of the flash suppressor to the Mod 3 barrel and a different type of cocking handle. The Internal components of the Mk 19 Mod 0 are different from the Mk 19 Mod 0 and the parts are not interchangeable. The Mk 19 Mod 3 is now in use by all branches of the US military. (Photo: US Navy)

Specifications, Machine Gun 40mm Mk 19 Mod 0:

Caliber ………………………………………………… 40x53mm SR
Weight ………………………………………………… 46 lbs.
Length ………………………………………………… 34 in.
Width ………………………………………………….. 8.5 in.
Height …………………………………………………. 7.5 in.
Mode of Operation ……………………………….…. Semi- or Full Automatic
Feed ………………………………………………….. Left Hand
Maximum Range ……………………………………. 2,200 meters
Maximum Effective Range …………………………. 1,600 meters
Muzzle Velocity ……………………………………… 880 feet per second
Barrel Length ………………………………………… 12 in.
Cooling ……………………………………………….. Air

© 2005 Bob Stoner R4