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==External links==
==External links==
{{Commons|M3 Grease gun}}
{{Commons|M3 Grease gun}}
* [http://www.dogswar.ru/strelkovoe-oryjie/pistolety-pylemety/4059-pistolet-pylemet-m3-.html M3 submachine, M3A1 «Grease gun»]
* [http://www.world.guns.ru/smg/smg32-e.htm Modern Firearms]
* [http://www.world.guns.ru/smg/smg32-e.htm Modern Firearms]
* [http://www.olive-drab.com/od_other_firearms_smg_m3.php3 Olive-Drab.com]
* [http://www.olive-drab.com/od_other_firearms_smg_m3.php3 Olive-Drab.com]

Revision as of 09:18, 10 April 2011

Submachine Gun, Cal. .45, M3
World War II era Guide Lamp M3 submachine gun with 30-round magazine and other accessories. The Buffalo Arms bolt in this original M3 is dated January 1944.
TypeSubmachine gun
Place of origin United States
Service history
In service1942–1992 (US)
Macedonia 1999-
Philippines (Revived 2004-)
Used bySee Users
WarsWorld War II,[1] Chinese Civil War, Korean War,[1] Bay of Pigs Incident, Vietnam,[1] Falklands War[2]
Production history
DesignerGeorge Hyde
Designed1942
ManufacturerGeneral Motors, others
Unit costApprox. US$20[3]
Produced1943–1945
No. built~700,000 [1]
VariantsM3A1, PAM1, PAM2
Specifications
MassM3: Template:Lb to kg
M3A1: Template:Lb to kg
LengthTemplate:In to mm stock extended / 22.8 in (579.1 mm) stock collapsed
Barrel length8 in (203.2 mm)
Cartridge.45 ACP
9x19mm Parabellum
ActionBlowback, open bolt
Rate of fire450 rounds/min cyclic
Muzzle velocity920 ft/s (280 m/s)
Effective firing rangeSights set to 100 yards (91 m) (9mm), 50 m[4] (.45 ACP)
Feed system30-round detachable box magazine
SightsFixed rear peep sight and blade foresight

The M3 was an American .45-caliber submachine gun that entered U.S. Army service on Dec. 12, 1942, as the United States Submachine Gun, Cal. .45, M3 and began to replace the .45-caliber Thompson series submachine guns: the M1928A1, M1 and M1A1 that were slowly being withdrawn from use.

The M3 was designed from the outset as a more cost-effective alternative to the Thompson, optimized for mass production. The M3 is commonly referred to as the "grease gun", owing to its visual similarity to the common mechanic's tool.[5]

History

M3 in use in Brittany, France, August 1944.

In 1941 the U.S. Army Ordnance Board observed the effectiveness of submachine guns employed in Western Europe, particularly the German 9mm MP 40 and British Sten guns, and initiated a study to develop its own Sten-type submachine gun in October 1942.[5] The Ordnance Department requested the Army to submit a list of requirements for the new weapon, and Ordnance in turn received a separate list of requirements from both the Infantry and Cavalry branches for a shoulder-fired weapon with full- or semi-automatic fire capability in caliber .45 ACP or .30 Carbine[6]. The two list of requirements received by Ordnance were then reviewed and amended by officials at Aberdeen Proving Ground. The amended requirement called for an all-metal weapon of sheet metal construction[7] in .45 ACP caliber, designed for fast and inexpensive production with a minimum of machining, and featuring a dual auto and semi-automatic fire capability, a heavy bolt to keep the cylic rate under 500rpm, and the ability to place 90 per cent of all shots fired from a standing position in full-automatic mode on a 6x6 foot target at a range of 50 yards.[8] The benchmark for testing the M3's performance would be the M1928A1 Thompson.[9]

Tasked with designing the new weapon was George Hyde of General Motors's Inland Division, while Frederick Sampson, Inland Division's chief engineer, was responsible for preparing and organizing tooling for production. The original T15 specifications of 8 October 1942 were altered to remove a semi-automatic fire function, as well as to permit installation of a kit to convert the weapon's original .45 caliber to that of 9mm Parabellum.[10] The new designation for the 9mm/.45 full-automatic-only weapon was the T20.[11] Five prototype models of the .45 T20 and five 9mm conversion kits were built by General Motors for testing. At the initial military trials, the T20 successfully completed its accuracy trials with a score of 97 out of 100.[12] In the endurance test, the test weapon fired more than 5,000 rounds of brass-case ammunition with only two failures to feed).[13]. Several other minor improvements were incorporated into the design before it was approved for production at GM's Guide Lamp Division in Anderson, Indiana in December 1942 as the U.S. Submachine Gun, Caliber .45, M3. Close to 600,000 weapons were assembled by the end of World War II, including approximately 25,000 models chambered for the 9x19mm Parabellum cartridge (converted by swapping out the barrel, bolt and applying a magazine well adapter for use with Sten magazines), which were delivered to the OSS in 1944. The OSS also requested approximately 1,000 .45-caliber M3 submachine guns with an integral sound suppressor (designed by Bell Laboratories).

With its stamped, riveted, and welded construction, the M3 was originally designed as a minimum-cost small arm, to be used and discarded once it became inoperative.[14][15] As such, replacement parts and sub-assemblies were not made available to unit-, depot-, or ordnance-level commands at the time of the M3's introduction to service.[16][17]

Design details

The M3 was an automatic, air-cooled blowback-operated weapon that fired from an open bolt. The weapon was striker fired with the fixed firing pin contained inside of the bolt. The bolt was drilled longitudinally to support two parallel guide rods, upon which were mounted twin return (recoil) springs. This configuration allowed for larger machining tolerances while providing operating clearance in the event of dust, sand, or mud ingress.[18] The M3 featured a spring-loaded extractor which was housed inside the bolt head, while the ejector was located in the trigger group.[19] Like the British STEN, time and expense was saved by cold-swaging the M3's barrel.[20]

Operating mechanism

A diagram of the M3 illustrating function.

The operating sequence was as follows: the bolt was cocked to the rear using the retracting handle. When the trigger was pulled, the bolt was driven forward by the recoil springs, stripping a round from the feed lips of the magazine and guiding the round into the chamber. The bolt then continued forward and the firing pin struck the cartridge primer, igniting the round, resulting in a high-pressure impulse, forcing the bolt back against the resistance of the recoil springs and the inertial mass of the bolt. By the time the bolt and empty casing have moved far enough to the rear to open the chamber, the bullet has left the barrel and pressure in the barrel has dropped to a safe level. The M3's comparatively low cyclic rate was a function of the relatively low pressure generated by the .45 ACP round, a heavy bolt, and recoil springs with a lighter-than-normal compression rate.

Features

M3 receiver markings

The fixed sights consisted of a rear aperture sight pre-set for firing at 100 yards (approximately 91 m) and a front blade foresight.

The weapon's only safety was the hinged ejection port cover. This cover had a projection on the underside that engaged a notch on the bolt, locking the latter in its forward and rearmost positions. The M3 had no mechanical means of disabling the trigger, and the insertion of a loaded magazine would load the gun. Unlike the Thompson, the M3 fed from a double-column, single-feed detachable box magazine which held 30 rounds and was patterned after the British Sten magazine; the single-feed design proved difficult to load by hand, and was more easily jammed by mud and dirt than double-column, double-feed designs like the Thompson. Additionally, the feed lips of the single-feed design proved more susceptible to feed malfunctions when bent or damaged. In response, some users would tape two M3 magazines together in opposing directions, so that the user could eject a spent or malfunctioning magazine and rotate the assembly to reload. On the right hand side of the receiver, just forward and above the trigger, was the retracting handle assembly which consisted of nine parts.[18] As the handle was pulled to the rear, a pawl would rise up to and engage a notch in the bottom of the bolt, pushing the bolt to the rear until it locked back on the sear.

The gun used metal stamping and pressing, spot welding and welding extensively in its construction, reducing the number of man-hours required to assemble a unit. Only the barrel, bolt and firing mechanism were precision machined. The receiver consisted of two sheet metal halves welded together to form a cylinder. At the front end was a knurled metal cap which was used to retain the removable barrel. The cold-swaged, rifled barrel had 4 right-hand grooves. M3 and M3A1 submachine guns could be fitted with an optional, detachable flash hider, though none saw any service in World War II.[21] Projecting to the rear was the one-piece wire stock made from a formed steel rod that telescoped into tubes on both sides of the receiver. Both ends of the stock were tapped and drilled so that it could be used as a cleaning rod. It could also be used as a disassembly tool or as a wrench used to unscrew the barrel cap.

The M3 had been originally designed as a disposable small arm, to be used and discarded once it became inoperative. However, in 1944, a shortage of new M3 weapons forced U.S. Army Ordnance workshops to fabricate pawl springs and other parts to keep existing weapons operational.[22][23]

Variants

M3A1

In December 1944 a modernized version of the M3 was introduced into service known as the M3A1, with all parts except the bolt, housing assembly, and receiver interchangeable with those of the M3. The M3A1 had several improvements, the most significant was the elimination of the troublesome crank-type retracting lever assembly, replaced by a recessed cocking slot machined into the top front portion of the bolt, allowing it to be cocked with the user’s finger. The retracting pawl notch was removed, and a clearance slot for the cover hinge rivets was added. The ejection port and its cover were lengthened to allow the bolt to be drawn back far enough to be engaged by the sear, and the safety lock was also moved further to the rear on the cover. To facilitate loading the single-feed magazine, a magazine loading tool was welded to the wire stock; it also served as a cleaning rod stop. The barrel bushing received two flat cuts that assisted in barrel removal by using the stock as a wrench. The barrel ratchet itself was redesigned to provide a longer depressing level for easier disengagement from the barrel collar. Furthermore, the spare lubricant clip (located on the left side of the cocking lever assembly) was removed, replaced with an oil reservoir and an oiler in the pistol grip of the receiver assembly. The stylus on the oiler cap could also double as a drift to remove the extractor pin.

Because it had already been issued in large numbers, the existing M3 magazine design was retained. In an effort to improve reliability, plastic caps were issued to fit over the feed lips of loaded magazines in order to protect the feed lips and to keep out dirt and debris.[24]

The modifications resulted in a reduced weight and improved reliability, improved maintenance, and eased field stripping (in the original M3 it was necessary to remove the trigger guard and detach the cocking crank assembly from the receiver housing before unscrewing the barrel, whereas the M3A1 required the user to merely unscrew the barrel). Many M3 guns were converted to the improved M3A1 configuration: during the conversion, armorers frequently removed the M3 cocking handle, leaving the rest of the now-redundant cocking mechanism inside the subframe.[25] Overall, the M3A1 was seen by most soldiers and Ordnance technicians as an improvement over the M3. However, complaints of accidental discharge continued to occur even as late as the Korean War.[25] These incidents were sometimes caused by dropping the weapon on a hard surface with an impact sufficient to knock open the ejection port cover and propel the bolt backwards (but not enough to catch the sear). The return springs would then propel the bolt forward to pick up a cartridge from the magazine and carry it into the chamber, where the bolt's fixed firing pin struck the primer upon contact.[25][26]

In 1945, the Guide Lamp factory manufactured close to 15,500 M3A1 submachine guns. During the Korean War, Ithaca Gun Co built another 33,000.

The M3 and M3A1 were mostly withdrawn from U.S. service in 1957; however, they continued to be used until the mid 1990s by armored vehicle crews and truck drivers. For example, during the Gulf War of 1991, drivers of the 19th Engineer Battalion, attached to the 1st Armored Division, were deployed with the M3A1.

Foreign variants

In 1955, M3 production was initiated at the Argentine FMAP (Fábrica Militar de Armas Portátiles) factory in the city of Rosario.[27] This version is known as the PAM1 and was chambered in 9x19mm Parabellum. A version called the PAM2 with a grip safety feature was also produced.

Users

Philippine Naval Special Warfare Group members conduct interdiction training with the U.S. Coast Guard in Cebu City, 2009. Two of them are armed with M3s.

See also

References

  1. ^ a b c d e Bishop, Chris. Guns in Combat. Chartwell Books, Inc (1998). ISBN 0-7858-0844-2.
  2. ^ "Argentina: Land Weapons and Vehicles". Britain's Small Wars. Retrieved 2009-04-06. {{cite web}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
  3. ^ Carter, Gregg Lee: Guns in American Society: An Encyclopedia of History, Politics, Culture, and the Law, page 588. ABC-CLIO, 2002.
  4. ^ http://world.guns.ru/smg/smg32-e.htm
  5. ^ a b Ingram, Mike: The MP40 Submachine Gun, page 85. Zenith Imprint, 2001.
  6. ^ Iannamico, Frank. The U.S. M3-3A1 Submachine Gun, Harmony Maine: Moose Lake Publishing, ISBN 0970195443, 9780970195449 (1999), pp. 22-23
  7. ^ Similar to the British STEN.
  8. ^ Iannamico, p. 24
  9. ^ Iannamico, p. 24
  10. ^ Iannamico, p. 34
  11. ^ Iannamico, p. 34.
  12. ^ Iannamico, p. 34
  13. ^ Iannamico, p. 34
  14. ^ Dunlap, Roy, Ordnance Went Up Front, Samworth Press (1948), p. 300
  15. ^ 2nd Ranger Battalion, World War II Living History Group, M3A1 Submachine Gun
  16. ^ Dunlap. p. 300
  17. ^ 2nd Ranger Battalion, M3A1 Submachine Gun
  18. ^ a b Ingram, 87
  19. ^ TM9-1005-229-35 repair manual, Sep 1969; Extractor M3 and M3A1 B-3 Item 5, Ejector M3 B-5 item 12, M3A1 B-4 item 2
  20. ^ Iannamico, pp. 45-46
  21. ^ Iannamico, pp. 131-132: A conical sheetmetal designated Hider, Flash T-34 was developed in 1945; a prototype only, few were produced. A later production flash hider designated Hider, Flash M9 was produced in time to see service during the Korean War.
  22. ^ Dunlap, Roy, Ordnance Went Up Front, Samworth Press (1948), p. 300
  23. ^ 2nd Ranger Battalion, World War II Living History Group, M3A1 Submachine Gun. Retrieved on September 19, 2008.
  24. ^ Hogg, Ian V. and Weeks, John, Military Small Arms of the 20th Century, 6th ed. DBI Books ISBN 0873491203, p.246
  25. ^ a b c Hackworth, David H. and Sherman, Julie, About Face: The Odyssey of an American Warrior, New York: Simon and Schuster (1989) ISBN 0671526928, p. 154
  26. ^ Iannamico, pp. 79-80
  27. ^ *Julio S. Guzmán, Las Armas Modernas de Infantería, Abril de 1953
  28. ^ Gander, Terry J.; Hogg, Ian V. Jane's Infantry Weapons 1995/1996. Jane's Information Group; 21 edition (May 1995). ISBN 978-0710612410.
  29. ^ a b c d e f g Jones, Richard D.; Ness, Leland S., eds. (January 27, 2009). Jane's Infantry Weapons 2009/2010 (35th ed.). Coulsdon: Jane's Information Group. ISBN 9780710628695.
  30. ^ "Chinese copy of US M3A1 Grease Gun". Retrieved 2008-09-19.
  31. ^ "M3A1 Grease Gun". Retrieved 2008-09-19.
  32. ^ "演習場で大活躍!自衛隊の火器(本物)" (in Japanese). Retrieved 2008-09-19.
  33. ^ "9mm機関けん銃" (in Japanese). Retrieved 2009-11-04.
  34. ^ "11.4mm短機関銃M3A1" (in Japanese). Retrieved 2009-11-04.
  35. ^ "11.4mm短機関銃 M3A1" (in Japanese). Retrieved 2009-11-04.
  36. ^ a b "M3 Grease Guns Re-issued". Retrieved 2008-09-19.
  37. ^ "New Sights for a Revived Workhorse: The M3 SpecOps Generation 2". Retrieved 2008-09-19.

Bibliography

  • Dunlap, Roy F., Ordnance Went Up Front, Samworth Press, 1948.
  • Ingram, Mike (2001). The MP40 Submachine Gun. Zenith Imprint. ISBN 0760310149. {{cite book}}: Cite has empty unknown parameter: |coauthors= (help)
  • Nelson, Thomas B. The World's Submachine Guns, TBN Enterprises, 1963.
  • Weeks, John, WWII Small Arms, Galahad Books, 1980.
  • Iannamico, Frank A., The U.S. M3-3A1 Submachine Gun, Moose Lake Publishing, 1999.
  • Iannamico, Frank A., United States Submachine Guns, Moose Lake Publishing, 2004.
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