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Mk 19 Grenade Machine Gun

Program History

In 1962, the US Navy introduced the first rapid fire grenade launcher using the 40x46mm ammunition the US Army had developed in the 1950s as part of the development of infantry grenade launchers that led to the M79. Though the weapon, designated as the Mk 18 Mod 0, represened a first step it was a relatively crude weapon. With a split-breech design patented by the Honeywell Corporation, the weapon was driven by a manually operated crank, similar to the guns produced by Dr. Richard Gatling in the 19th century. It could be fired as fast as the operator could manipulate the crank and used non-disintegrated fiberglass tape belts. Honeywell and Aeronautical Products Division of Hopkins Minnesota produced some 1,200 Mk 18 Mod 0s between 1965 and 1968, with the weapon being fielded in Vietnam mounted on Navy river patrol craft.

In the early 1960s, the US Army also developed a higher velocity 40x53mm grenade. It designed weapons, primarily for aircraft (fixed and rotary wing) applications. The first of these launchers, the M75 and the M129 were designed with these applications in mind and were electrically powered, requiring a power source. Attempts to utilize both as an infantry weapon were made using either an attached electric power source or a manual crank as with the Mk 18 Mod 0. The crank operated version of the M129 was designated as the XM173. The US Navy desired a weapon to replace the Mk 18 Mod 0 that was self-powered like more traditional machine guns then in service.

In July 1966, Naval Ordnance Systems Command directed Naval Ordnance Station Louisville in Louisville, Kentucky to develop two prototype weapons, one using the low velocity 40mm grenades and one using the high velocity ammunition. The high velocity prototype became the Mk 19 Mod 0, while the low velocity one became the Mk 20 Mod 0. The urgent requirement meant that the development of the weapon was greatly sped up and the Mk 19 Mod 0 rushed into production. The Mk 19 Mod 0 was quickly found to be neither reliable enough nor safe enough for military use.

A program to improve the design was approved in 1969, and the upgraded Mk 19 Mod 1 appeared in 1971. Reliability and safety issues were effectively mitigated in the new version and the theweapon performed effectively in Navy riverine patrol craft in Vietnam. With this successful product, broader applications for the Mk 19 Mod 1 were proposed and interest in the system greatly increased.

Concerns over the rushed nature of the Mk 19 Mod 1's development saw the approval for a further upgrade program in 1973. The resulting weapon had a more finished look to it. However, the massive tweaking of the design meant that the resulting Mk 19 Mod 2 was found to be almost completely non-functional.

In 1976, a complete redesign of the weapon resulted in the Mk 19 Mod 3. The Mod 3 was extremely different visually from its predecessors as well, incoporating visual features that had been intially found on NOS Louisville's experimental EX 6 Mod 0 combination 20/30mm cannon trialed in the 1950s. The feed tray cover was more reminiscent of that weapon.

The US Army adopted the Mk 19 Mod 3 in 1983, with TACOM-ARDEC had since suggested modifications to the system, which enabled the Army to deploy the Mk 19 in the harsh environments encountered during world-wide operations and therefore enhanced its performance. The Mk 19 was adopted by the US Army to replace or augment selected M2 .50 caliber machine guns throughout the Army. The Mk 19 Mod 3 was used mounted on HMMWV's, trucks, and M88 Recovery Vehicles, and other systems to deliver intense suppressive fire against enemy personnel and lightly armored vehicles or bunkers. The Army used the Mk 19 Mod 3 within the tactical environment for defense, retrograde, patrolling, rear area security, MOUT, and special operations. In use by the US Navy, the system was also adopted by the US Marine Corps and the US Air Force for a variety of ground applications. In 1991, the Army deployed the system in Southwest Asia during Operation Desert Storm and devastated enemy infantry.

One of the US Army National Guard's (ARNG) critical readiness requirements was small arms and crew-served weapons modernization. With the advent of Army Transformation to Units of Action (UA's) in the late 1990s, the ARNG had documented a shortfall of 3,377 Mk 19 Mod 3's. Operational requirements resulting from the beginning of the Global War on Terror in 2001 resulted in extensive unit-to-unit transfers of Mk 19 Mod 3's to deploying units. M2 .50 calber machine guns and operational barrels were also in short supply. As the primary supressive weapon for combat support and combat service support units, any shortage of these weapons was seen as a critical issue.

The Requirement Definition Document (RDD) validated an ARNG requirement by 2005 for 9,159 Mk 19 Mod 3's at a cost of $15,500 each. On hand were 5,782 Mk 19 Mod 3's, the majority of which were deployed. Fielding to fill the previous ARNG requirement was completed in 2003 and the new increased requirement had not yet been programmed at that time. At that time, the Mk 19 Mod 3 Unfunded Requirement (UFR) was for 3,377 units and could potentially increase as ARNG modularity above UA level was documented. The only alternative weapon systems were the XM307/XM312 Advanced Crew Served Weapons still under development with no projected fielding date.

Funding the Mk 19 Mod 3 would give National Guard Soldiers the same capability as Active Army Forces to deploy and operate with maximum effectiveness on all fronts of the Global War on Terror. It greatly contributed to their ability to rapidly defend themselves with high volume, suppressive fire in adverse conditions. Failure to fund the Mk 19 Mod 3 would increase soldier risk and the costs of pre-deployment cross-leveling, which also degraded the ARNG's ability to train for and execute both its federal and state missions.

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