40 mm machine grenade launcher Mk 20
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The Mk 20 Mod 0 is a fully automatic grenade launcher of American origin. It was developed and produced by Naval Ordnance Station Louisville , a US Navy facility .
Development and use
During the Vietnam War , the US Navy recognized the need for effective short and medium-range support weapons that could be used on River Patrol Boats (PBR) . The US Navy boats patrolled the great rivers and inland waters of Vietnam and had the task of controlling and dominating the banks. To do this, they need great firepower from weapon systems, which had to be compact and light due to the limitations of boat size. Due to the dense vegetation in many places, a long fire range was not necessary. The Navy's solution was a rapid-fire grenade launcher with a caliber of 40 millimeters . Three technically very different systems were created:
- The Mark 18 grenade launcher is a manually operated weapon, i.e. a hand crank, with an unusual split chamber that does not close completely even when the shot is fired . This is possible by using the 40 × 46 mm grenade, which operates with a comparatively low internal pressure.
- The Mark 19 machine grenade launcher has a more conventional structure and was designed to use the more powerful 40 × 53 mm grenade. However, it was not able to convince in the first three development stages Mod 0 to Mod 2.
- The Mark 20 machine grenade launcher described here was designed like the Mark 18 for the 40 × 46 mm grenade. Development began in August 1966, and in May 1970 the weapon was officially introduced by the US Navy and used on its river boats from then on. Only after the Mark 19 grenade launcher had reached a satisfactory level in the fourth development stage Mod 3 did it replace the Mark 20 from 1983.
technology
The grenade launcher Mark 20 operates on the uncommonly functional principle of a zuschießenden Blow-forward weapon . Before the trigger is actuated , the barrel is in an advanced position, the grenades , which are fed in via an ammunition belt, lie open in front of the breech block . If the trigger in the form of a button between the two handles of the weapon is actuated, a spring pushes the barrel backwards so that it slides over the grenade. At the end of its movement, the barrel releases the shot. The gas pressure of the propellant charge and the movement of the grenade in the barrel itself push the barrel forward again; this movement also actuates the belt feed mechanism so that a new grenade is brought in front of the breech block. The grenade launcher has a semi-automatic one-shot mode, and a fully automatic firing mode, i.e., the existing grenades with a while pressing the trigger button cadence fired from about 250 to 275 rounds per minute.
Technical specifications
| Mk-20 machine grenade launcher | |
|---|---|
| Caliber: | 40 × 46 mm SR |
| fire rate | 240 rounds / min. |
| Muzzle velocity | 73 m / s |
| Max. Range | 400 m |
| Max. effective range | 350 m |
| length | 79.2 cm |
| width | 23.6 cm |
| height | 24.4 cm |
| Weight | 11.8 kg |
See also
- Howa Type 96 , another machine grenade launcher that works according to the blow-forward principle
literature
- George M. Chinn, The Machine Gun. Volume V, 1987, pp. 507-511.
Web links
- Bob Stoner, NOS Louisville Mk 20 Mod 0 Automatic 40mm Grenade Launcher on warboats.org , published 2005, last accessed January 13, 2018.
Remarks
- ↑ Ian McCollum, Vietnam Mk18 Mod0 Hand-Crank Grenade Launcher on forgottenweapons.com , published December 20, 2017, last accessed January 13, 2018.
- ↑ Information according to Chinn, Machine Gun, p. 509, partially converted into the metric system; different information from Stoner, Mk 20, 2005.
- ↑ Stoner, Mk 20, 2005, gives a rate of 250–275 rounds / min; Chinn, Machine Gun, p. 509 gives 240 rounds / min as regular cadence and 425 rounds / min as maximum cadence.