M40 recoilless rifle
|M40 Recoilless Rifle|
Greek infantry with an M40
|Place of origin||United States|
|In service||Mid 1950s–present|
|Used by||See Users|
|Weight||209.5 kg (462 lb)|
|Length||3.404 m (11 ft 2 in)|
|Height||1.12 m (3 ft 8 in)|
|Shell||106×607mmR (HEAT, HEP, HEAP, Canister)|
|Caliber||106 mm (4.2 in)|
|Elevation||−17° to +65° (between mount legs)
−17° to +27° (over mount leg)
|Muzzle velocity||503 m/s (1,650 ft/s) (M344 HEAT)|
|Effective firing range||1,350 m (1,480 yd)|
|Maximum firing range||6,870 m (M346A1 HEP-T)|
The M40 recoilless rifle is a lightweight, portable, crew-served 106 mm weapon intended primarily as an anti-tank weapon made in the United States. The weapon is commonly described as being 106 mm, but it is in fact 105 mm; the 106 mm designation was designed to prevent confusion with the incompatible 105 mm ammunition from the failed M27. It could also be employed in an antipersonnel role with the use of the antipersonnel-tracer flechette round. It can be fired primarily from a wheeled ground mount. The air-cooled, breech-loaded, single-shot rifle fired fixed ammunition. It was designed for direct firing only, and sighting equipment for this purpose was furnished with each weapon.
The M27 recoilless rifle was a 105-mm weapon developed in the early 1950s and fielded in the Korean War. Although a recoilless rifle of this caliber had been a concept since the Second World War, the weapon was hurriedly produced with the onset of the Korean War. The speed with which it was developed and fielded resulted in problems with reliability caused by trunnions that were mounted too far to the rear. The M27 was also considered too heavy by the U.S. Army and had a disappointing effective range due to the lack of a spotting rifle. Taking the M27 as the basis for a new design, the Army developed an improved version of the M27 that was in 1955 type-designated the M40 106-mm recoilless rifle. Originally along with its type-designation it was also given the official name BAT for Battalion Anti-Tank gun, but that was soon dropped. Although unsuitable for military purposes, M27 recoilless rifles were used to trigger controlled avalanches at ski resorts and mountain passes in the United States.
The M40 primarily saw action during the Vietnam War and was later replaced by the BGM-71 TOW anti-tank missile system. The weapon was also used by anti-communist forces in Angola mounted on Land Rovers.
The M40 is shaped like a long tube with an M8 0.50 cal spotting rifle above. The spotting rifle fires a round whose trajectory closely matches that of the 106 mm round and gives off a puff of smoke on impact with the target. On the left hand side, there is an elevating wheel, in the centre of which is the trigger wheel used to fine adjust the elevation and at the same time firing the spotting rifle when pulled, and the gun when pushed. The mounting is a tripod, but the front leg has a castoring wheel. On top of the mount is a traverse wheel. On the centre of the traverse wheel is a locking wheel, when the wheel is down, the rifle is locked in traverse, and can only be moved right and left with the traverse wheel. When the wheel is raised, the rifle can be traversed by hand. Austria produced a two-wheeled mount for the M40.
The whole mounting can be placed on an M151 Jeep for mobile use. It has also been mounted on Willys Jeep M 38A1 Land Rover Defenders, M113s, Mercedes-Benz G-Wagen, HMMWVs, Hotchkiss M201 jeeps, Toyota Land Cruisers, AIL Storms and M274 Mechanical Mules. They were also used on US Navy minesweepers (MSO) during Operation Market Time in Vietnam.
A special vehicle called Ontos carried six M40s. A version specific to the T195E5 mount, the M40A1C, was used. It was used only by the U.S. Marine Corps. Japan produced a self-propelled gun called the Type 60 which carried two side by side. Some Pakistani M113s have a dual mounting.
The M40 was a very successful export item and continues to be used by South Korea (ROK), Ecuador, Egypt, Estonia, Greece, Honduras, Iran, Israel, Lebanon, Malaysia, Mexico, Morocco, the Philippines, Taiwan (Republic of China Marine Corps), Turkey, Colombia, Cambodia, Vietnam, Venezuela and many others, as well as anti-government forces in the Libyan Civil War and Syrian civil war.
In the period 1958–1990 the antitank companies of the Swiss Army Infantry Regiments were equipped with 12 M40 guns.
Ammunition for the 106 mm rifle was issued as one-piece fixed cartridges. The term "fixed" means that the projectile and the cartridge case are crimped together. This ensures correct alignment of the projectile and the cartridge case. It also permits faster loading because the projectile and the cartridge case are loaded as one unit. The rear end of the cartridge case is perforated, to allow the propellant gas to escape through the vented breech, thus neutralizing recoil. Most projectiles (except HEAT) used are pre-engraved, that is, the rotating bands are cut to engage the rifled bore. If the round was not rotated slightly when loading the M40 it could result in jamming in the breach.
Types of ammunition included HEAT, High Explosive Plastic-Tracer (HEP-T), canister, High Explosive Anti Personnel, and the M368 dummy round which could not be fired and was used for crew drill. The original U.S. HEAT round penetrated more than 400 mm of armor. Near the end of the M40's service life, both Austria and Sweden produced HEAT rounds for the weapon capable of penetrating more than 700 mm of armor.
|M581||APERS||9.89 kg||flechettes||4.94 kg||N/A||300 m|
|M-DN11||HEAP||3.6 kg||Hexogen||0.77 kg||N/A||1500 m|
|NR 601||HESH-T||7.8 kg||Comp. A3||N/A||N/A||N/A|
|PFF||HE||9.89 kg||Comp. B||N/A||N/A||N/A|
|M346A1||HEP-T||7.96 kg||Comp. A3||3.5 kg||N/A||N/A|
|M344A1||HEAT||7.96 kg||Comp. B||1.27 kg||over 400 mm||1350 m|
|106 3A||HEAT-T||5.5 kg||Octol||1.0 kg||over 700 mm||2000 m|
|RAT 700||HEAT||5.0 kg||N/A||1.1 kg||over 700 mm||N/A|
The ammunition for the 0.50 cal spotting rifle is not .50 BMG. The round used is a special round designed to simulate the flight path of the 106 mm ammunition.
Although the spotting rifle could conceivably be used in an antipersonnel role, historical U.S. military doctrine strongly discouraged this use. This limitation was entirely tactical in nature, having been intended to help conceal the vulnerable M40 and its crew from the enemy before the main anti-tank gun could be fired; however, this restriction is believed to be the source of a long-standing misconception that the laws of war restrict the use of .50-caliber projectiles against enemy personnel more generally.
- Dominican Republic
- El Salvador
- Italy (former operator)
- Myanmar Used for bunker busting and anti-personnel/infantry support role in counter-insurgency campaigns.
- New Zealand
- South Africa: South African National Defence Force.
- South Korea
- Syria: Videos show Syrian rebels (Free Syrian Army) operating and firing M40 Recoilless Rifles.
- United States
- "Anti Tank weapons". official web site of the South African army. Retrieved 2011-05-08.
- U.S. Army Technical Manual 43-0001-28, p. 5-27, April 1994.
- Bob Stoner GMCM (SW) Ret. (2005). "M40A1 106MM Recoilless Rifle with M8C Spotting Rifle".
- "M40 106mm Recoilless Rifle". globalsecurity.org. Retrieved 2012-09-20.
- John Weeks, Men against tanks, New York: Mason/Charter, 1975.
- "Antitank Rifle Mounted On Jeep" Popular Mechanics, March 1955, p. 147.
- Comment by Ken Estes at tanknet.org.
- McNally, Brendan (May 31, 2013). "Ancient U.S. Weapon Makes a Surprise Reappearance in Syria". Wired.
- ANTI-TANK GUN 106
- "M40 106mm recoilless Rifle". M40 106mm Recoilless Rifle. Global Security. Retrieved 27 January 2014.
- JAH, pp. 140-141.
- Probably defeats ~ 200 mm of armor.
- After penetrating explosive reactive armor.
- Parks, Maj W. Hays (January 1988). "Killing A Myth". Marine Corps Gazette. Retrieved 20 February 2014.
- Army Recognition Alain Servaes. "Index of military army equipment from Salvadoran Army of El Salvador Index des équipements militaires de l'armée du Salvador Salvadorienne". Retrieved 13 February 2015.
- "sodur.com". Retrieved 13 February 2015.
- (JAH) Terry Gander and Ian Hogg (ed.), Jane's Ammunition Handbook 1994, Coulsdon: Jane's Information Group Ltd., 1993.
- (JIW) Richard Jones and Leland Ness (ed.), Jane's Infantry Weapons 2007–2008, Coulsdon: Jane's Information Group Ltd., 2007.
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