ArmaLite AR-15

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ArmaLite AR-15
ArmaLite AR-15 SPAR 3240 DEC. 17. 2004.png
ArmaLite AR-15 with 25-round magazine
Type Assault rifle[1]
Place of origin United States
Service history
In service 1959–1990s
Wars Vietnam War
Production history
Designer Armalite, Jim Sullivan and Bob Fremont[2]
Designed 1956[3]
Manufacturer
Produced 1959-1964[3]
Specifications
Weight 6.55 lb (2.97 kg) with 20 round magazine[4]
Length 39 in (991 mm)[4]
Barrel length 20 in (508 mm)

Cartridge .223 Remington or 5.56mm
Action Gas-operated, rotating bolt (direct impingement)
Muzzle velocity 3,300 ft/s (1,006 m/s)[4]
Effective firing range 500 yd (457 m)
Sights Iron sights

The ArmaLite AR-15 is a select-fire[5], air-cooled, gas-operated, magazine-fed assault rifle[6] manufactured in the United States between 1959 and 1964. Designed by American gun manufacturer ArmaLite in 1956, it was based on its AR-10 rifle. The ArmaLite AR-15 was designed to be a lightweight assault rifle and to fire a new high-velocity, lightweight, small-caliber cartridge to allow the infantrymen to carry more ammunition (was later adopted as the M-16 Service Rifle).[7]

In 1959, ArmaLite sold its rights to the AR-10 and AR-15 to Colt due to financial difficulties, and limitations in terms of manpower and production capacity.[8] After modifications (most notably, the charging handle was re-located from under the carrying handle like AR-10 to the rear of the receiver),[9] Colt rebranded it the Colt ArmaLite AR-15. Colt marketed the redesigned rifle to various military services around the world and it was subsequently adopted by the U.S. military as the M16 rifle, which went into production in March 1964.[7][10]

Colt continued to use the AR-15 trademark for its line of semi-automatic-only rifles marketed to civilian and law-enforcement customers, known as Colt AR-15. The Armalite AR-15 is the parent of a variety of Colt AR-15 & M16 rifle variants.

History[edit]

After World War II, the United States military started looking for a single automatic rifle to replace the M1 Garand, M1/M2 Carbines, M1918 Browning Automatic Rifle, M3 "Grease Gun" and Thompson submachine gun.[11][12] However, early experiments with select-fire versions of the M1 Garand proved disappointing.[13] During the Korean War, the select-fire M2 Carbine largely replaced the submachine gun in US service[14] and became the most widely used Carbine variant.[15] However, combat experience suggested that the .30 Carbine round was under-powered.[16] American weapons designers concluded that an intermediate round was necessary, and recommended a small-caliber, high-velocity cartridge.[17]

However, senior American commanders having faced fanatical enemies and experienced major logistical problems during WWII and the Korean War,[18][19][20][21][22] insisted that a single powerful .30 caliber cartridge be developed, that could not only be used by the new automatic rifle, but by the new general-purpose machine gun (GPMG) in concurrent development.[23][24] This culminated in the development of the 7.62×51mm NATO cartridge.[23]

The United States Army then began testing several rifles to replace the obsolete M1 Garand. Springfield Armory's T44E4 and heavier T44E5 were essentially updated versions of the Garand chambered for the new 7.62 mm round, while Fabrique Nationale submitted their FN FAL as the T48. ArmaLite entered the competition late, hurriedly submitting several AR-10 prototype rifles in the fall of 1956 to the United States Army's Springfield Armory for testing.[25]

ArmaLite AR-10 with mounted bayonet made by Artillerie Inrichtingen (A.I.).

The AR-10 featured an innovative straight-line barrel/stock design, forged aluminum alloy receivers and with phenolic composite stocks.[26] It had rugged elevated sights, an oversized aluminum[27] flash suppressor and recoil compensator, and an adjustable gas system.[28] The final prototype, featured an upper and lower receiver with the now-familiar hinge and takedown pins, and the charging handle was on top of the receiver placed inside of the carry handle.[25] For a 7.62mm NATO rifle, the AR-10 was incredibly lightweight at only 6.85 lbs. empty.[25] Initial comments by Springfield Armory test staff were favorable, and some testers commented that the AR-10 was the best lightweight automatic rifle ever tested by the Armory.[29][30]

In the end the United States Army chose the T44 now called the M14 rifle[23] which was an improved M1 Garand with a 20-round magazine and automatic fire capability.[31][32][33] The U.S. also adopted the M60 general purpose machine gun (GPMG).[23] Its NATO partners adopted the FN FAL and HK G3 rifles, as well as the FN MAG and Rheinmetall MG3 GPMGs.

The first confrontations between the AK-47 and the M14 came in the early part of the Vietnam War. Battlefield reports indicated that the M14 was uncontrollable in full-auto and that soldiers could not carry enough ammo to maintain fire superiority over the AK-47.[31][34] And, while the M2 Carbine offered a high rate of fire, it was under-powered and ultimately outclassed by the AK-47.[35] A replacement was needed: A medium between the traditional preference for high-powered rifles such as the M14, and the lightweight firepower of the M2 Carbine.

Early ArmaLite AR-15 without magazine or flash hider

As a result, the Army was forced to reconsider a 1957 request by General Willard G. Wyman, commander of the U.S. Continental Army Command (CONARC) to develop a .223 caliber (5.56 mm) select-fire rifle weighing 6 lb (2.7 kg) when loaded with a 20-round magazine.[11] The 5.56mm round had to penetrate a standard U.S. M1 helmet at 500 yards (460 meters) and retain a velocity in excess of the speed of sound, while matching or exceeding the wounding ability of the .30 Carbine cartridge.[36] This request ultimately resulted in the development of a scaled-down version of the ArmaLite AR-10, called ArmaLite AR-15 rifle.[7][9][37]

In 1958, ArmaLite submitted ten AR-15s and one hundred 25-round magazines for CONARC testing.[9] The tests found that a 5- to 7-man team armed with AR-15s has the same firepower as 11-man team armed with M14s.[38] That soldiers armed with AR-15s could carry three times more ammunition as those armed with M14s (649 rounds vs 220 rounds).[39] And, that the AR-15 was three times more reliable than the M14 rifle.[9] However, General Maxwell Taylor, then Army Chief of Staff, "vetoed" the AR-15 in favor of the M14.[9] In 1959, ArmaLite now frustrated with the lack of results and suffering ongoing financial difficulties, sold its rights to the AR-10 and AR-15 to Colt.[8]

Colt era[edit]

Colt ArmaLite AR-15 Model 01 with 20-round magazine

After acquiring the AR-15, Colt promptly redesigned the rifle to facilitate mass production. Based on the final ArmaLite design, most notably, the charging handle was re-located from under the carrying handle, like the earlier AR-10 to the rear of the receiver, like the later M16 rifle.[9] Colt then renamed and rebranded the rifle "Colt ArmaLite AR-15 Model 01" After a far East tour, Colt made its first sale of Colt ArmaLite AR-15 rifles to Malaya on September 30, 1959. Colt manufactured their first batch of 300 Colt ArmaLite AR-15 rifles in December 1959.[40] Colt would go on to market the Colt ArmaLite AR-15 rifle to military services around the world.

In July 1960, General Curtis LeMay, then Vice Chief of Staff of the United States Air Force, was impressed by a demonstration of the AR-15 and ordered 8500 rifles.[41] In the meantime, the Army would continue testing the AR-15, finding that the intermediate cartridge .223 (5.56mm) rifle is much easier to shoot than the standard 7.62mm NATO M14 rifle.[42][43] In 1961 marksmanship testing, the U.S. Army found that 43% of AR-15 shooters achieved Expert, while only 22% of M-14 rifle shooters did so. Also, a lower recoil impulse, allows for more controllable automatic weapons fire.[44][45]

In the summer of 1961, General LeMay was promoted to Chief of Staff of the United States Air Force, and requested an additional 80,000 AR-15s. However, General Maxwell D. Taylor, now Chairman of the Joint Chiefs of Staff, (who repeatedly clashed with LeMay) advised President John F. Kennedy that having two different calibers within the military system at the same time would be problematic and the request was rejected.[46]:372 In October 1961, William Godel, a senior man at the Advanced Research Projects Agency, sent 10 AR-15s to South Vietnam. The reception was enthusiastic, and in 1962, another 1,000 AR-15s were sent.[47][46]:372–373 United States Army Special Forces personnel filed battlefield reports lavishly praising the AR-15 and the stopping-power of the 5.56 mm cartridge, and pressed for its adoption.[48][31]

Colt ArmaLite AR-15 Model 02 without magazine and new 1 in 12-inch (300 mm) rifling twist rate

The damage caused by the 5.56 mm bullet was originally believed to be caused by "tumbling" due to the slow 1 in 14-inch (360 mm) rifling twist rate.[31][46]:372 However, any pointed lead core bullet will "tumble" after penetration in flesh, because the center of gravity is towards the rear of the bullet. The large wounds observed by soldiers in Vietnam were actually caused by bullet fragmentation, which was created by a combination of the bullet's velocity and construction.[49][31][46]:372 These wounds were so devastating, that the photographs remained classified into the 1980s.[46]:373

However, despite overwhelming evidence that the AR-15 could bring more firepower to bear than the M14, the Army opposed the adoption of the new rifle.[7][31] U.S. Secretary of Defense Robert McNamara now had two conflicting views: the USAF's (General LeMay's) repeated requests for additional AR-15s and the ARPA report[50] favoring the AR-15, versus the Army's position favoring the M14.[31] Even President Kennedy expressed concern, so McNamara ordered Secretary of the Army Cyrus Vance to test the M14, the AR-15 and the AK-47. The Army reported that only the M14 was suitable for service, but Vance wondered about the impartiality of those conducting the tests. He ordered the Army Inspector General to investigate the testing methods used; the Inspector General confirmed that the testers were biased towards the M14.

In January 1963, Secretary McNamara received reports that M14 production was insufficient to meet the needs of the armed forces and ordered a halt to M14 production.[31] At the time, the AR-15 was the only rifle that could fulfill a requirement of a "universal" infantry weapon for issue to all services. McNamara ordered its adoption, despite receiving reports of several deficiencies, most notably the lack of a chrome-plated chamber.[51]

An early M16 rifle without forward assist

After minor modifications,[9] the new redesigned rifle was renamed the Rifle, Caliber 5.56 mm, M16.[7][10] Meanwhile, the Army relented and recommended the adoption of the M16 for jungle warfare operations. However, the Army insisted on the inclusion of a forward assist to help push the bolt into battery in the event that a cartridge failed to seat into the chamber. The Air Force, Colt and Eugene Stoner believed that the addition of a forward assist was an unjustified expense. As a result, the design was split into two variants: the Air Force's M16 without the forward assist, and the XM16E1 (AKA: M16A1) with the forward assist for the other service branches.

Photograph of Secret Service agent George W. Hickey with an ArmaLite AR-15 moments after President Kennedy was shot in Dallas on November 22, 1963.

In November 1963, McNamara approved the U.S. Army's order of 85,000 XM16E1s;[31][46]:380, 392 and to appease General LeMay, the Air Force was granted an order for another 19,000 M16s.[52][46]:380 In March 1964, the M16 rifle went into production and the Army accepted delivery of the first batch of 2129 rifles later that year, and an additional 57,240 rifles the following year.[10]

The Colt ArmaLite AR-15 was discontinued with the adoption of the M16 rifle. Most AR-15 rifles in U.S. service have long ago been upgraded to M16 configuration. The Colt ArmaLite AR-15 was also used by the United States Secret Service and other U.S. federal, state and local law enforcement agencies.

Shortly after the United States military adopted the M16 rifle, Colt introduced its line semi-automatic-only Colt AR-15 rifles, which it markets to civilians and law enforcement. Colt continues to use the AR-15 name for these rifles in order to pay homage to their predecessor the ArmaLite AR-15.

Features[edit]

Armalite AR-15[edit]

Early ArmaLite AR-15 without flash hider or magazine

The AR-15 is a select-fire, 5.56×45mm, air-cooled, direct impingement gas-operated, magazine-fed rifle, with a rotating bolt and straight-line recoil design. It was designed to be manufactured with the extensive use of aluminium and synthetic materials by state of the art Computer Numerical Control (CNC) automated machinery.

ArmaLite AR-15 with 25-round magazine and flash hider

The AR-15 is a Modular Weapon System. It is easy to assemble, modify and repair using a few simple hand tools, and a flat surface to work on. The AR-15's upper receiver incorporates the fore stock, the charging handle, the gas operating system, the barrel, the bolt and bolt carrier assembly. The lower receiver incorporates the magazine well, the pistol grip and the buttstock. The lower receiver also contains the trigger, disconnector, hammer and fire selector (collectively known as the fire control group). The AR-15's "duckbill" flash suppressor had three tines or prongs and was designed to preserve the shooter's night vision by disrupting the flash. Early AR-15's had a 25-round magazine. Later model AR-15s used a 20-round waffle-patterned magazine that was meant to be a lightweight, disposable item.[53][54] As such, it is made of pressed/stamped aluminum and was not designed to be durable.[53]

The AR-15's most distinctive ergonomic feature is the carrying handle and rear sight assembly on top of the receiver. This is a by-product of the design, where the carry handle serves to protect the charging handle.[55] The AR-15 rifle has a 500 mm (19.75 inches) sight radius. The AR-15 uses an L-type flip, aperture rear sight and it is adjustable with two settings, 0 to 300 meters and 300 to 400 meters. The front sight is a post adjustable for elevation. The rear sight can be adjusted for windage. The sights can be adjusted with a bullet tip or pointed tool.

"The (AR-15's) Stoner system provides a very symmetric design that allows straight line movement of the operating components. This allows recoil forces to drive straight to the rear. Instead of connecting or other mechanical parts driving the system, high pressure gas performs this function, reducing the weight of moving parts and the rifle as a whole."[56] The AR-15's straight-line recoil design, where the recoil spring is located in the stock directly behind the action,[55] and serves the dual function of operating spring and recoil buffer.[55] The stock being in line with the bore also reduces muzzle rise, especially during automatic fire. Because recoil does not significantly shift the point of aim, faster follow-up shots are possible and user fatigue is reduced.

Colt ArmaLite AR-15 (Model 601 & 602)[edit]

Colt ArmaLite AR-15 Model 01 with 20-round magazine, made from 1959-1964
Colt ArmaLite AR-15 Model 02 without magazine and new 1 in 12-inch (300 mm) rifling twist rate, made in 1964

Colt's first two models produced after the acquisition of the rifle from ArmaLite were the 601 and 602, and these rifles were in many ways clones of the original ArmaLite rifle (in fact, these rifles were often found stamped Colt ArmaLite AR-15, Property of the U.S. Government caliber .223, with no reference to them being M16s).[57]

The 601 and 602 are virtually identical to the later M16 rifle without the forward-assist. Like the later M16 rifle their charging handle was re-located from under the carrying handle like AR-10 to the rear of the receiver.[9] They were equipped with triangular fore-stocks and occasionally green or brown furniture. Their front sight had a more triangular shape. They had flat lower receivers without raised surfaces around the magazine well. Their bolt hold open device lacked a raised lower engagement surface and had a slanted and serrated surface that had to be engaged with a bare thumb, index finger, or thumb nail because of the lack of this surface. Their fire-selector was also changed from upward = safe, backward = semi-auto and forward = full-auto, to the now familiar forward = safe, upward = semi-auto, and backward = full-auto of the M16 rifle.[58]

The only major difference between the 601 and 602 is the switch from the original 1:14-inch rifling twist to the more common 1:12-inch twist. The 601 was first adopted by the United States Air Force, and was quickly supplemented with the 602s (AKA: XM16s) and later the 604s (AKA: M16s). Over time, the 601s and 602s were converted to M16 rifle configuration. The USAF continued to use ArmaLite AR-15 marked rifles well into the 1990s.

See also[edit]

Further reading[edit]

References[edit]

  1. ^ "REPORT OF TASK NO. 13A. TEST OF ARMALITE RIFLE. AR-15 (U)" (PDF). RESEARCH & DEVELOPMENT FIELD UNIT. Advanced Research Projects Agency. 31 July 1962. 
  2. ^ Ezell, Virginia Hart (November 2001). "Focus on Basics, Urges Small Arms Designer". National Defense. National Defense Industrial Association. Archived from the original on 2010-12-07. 
  3. ^ a b Hogg, Ian V.; Weeks, John S. (2000). Military Small Arms of the 20th Century (7th ed.). Iola, Wisconsin: Krause Publications. ISBN 978-0-87341-824-9. , p. 291
  4. ^ a b c Rifle Evaluation Study. US Army. Infantry Combat Developments Agency. February 17, 1978
  5. ^ http://www.dtic.mil/dtic/tr/fulltext/u2/343778.pdf Field Test Report, AR-15 Armalite Rifle. Final Report, OSD/ARPA Research and Development Unit - Vietnam. 20 August 1962
  6. ^ "REPORT OF TASK NO. 13A. TEST OF ARMALITE RIFLE. AR-15 (U)" (PDF). RESEARCH & DEVELOPMENT FIELD UNIT. Advanced Research Projects Agency. 31 July 1962. 
  7. ^ a b c d e Kern, Danford Allan (2006). The influence of organizational culture on the acquisition of the m16 rifle. m-14parts.com. A thesis presented to the Faculty of the US Army Command and General Staff College in partial fulfillment of the requirements for the degree MASTER OF MILITARY ART AND SCIENCE, Military History. Fort Leavenworth, Kansas
  8. ^ a b Bartocci, Christopher R. (July 16, 2012). "AR-15/M16: The Rifle That Was Never Supposed to Be". Gun Digest. Retrieved May 24, 2017. 
  9. ^ a b c d e f g h Kokalis, Peter G. Retro AR-15. nodakspud.com
  10. ^ a b c Report of the M16 rifle review panel. Department of the Army. dtic.mil. 1 June 1968
  11. ^ a b Ehrhart, Thomas P. (Maj.) (2009). Increasing Small Arms Lethality in Afghanistan: Taking Back the Infantry Half-Kilometer. US Army. 
  12. ^ The M16. By Gordon Rottman. Osprey Publishing, 2011. page 6
  13. ^ Schreier, Philip. "CUT DOWN in its Youth, Arguably Americas Best Service Rifle, the M14 Never Had the Chance to Prove Itself" (PDF). SSUSA. pp. 24–29, 46. 
  14. ^ Gordon Rottman (2011). The M16. Osprey Publishing. p. 6. ISBN 978-1-84908-690-5. 
  15. ^ Leroy Thompson (2011). The M1 Carbine. Osprey Publishing. p. 35. ISBN 978-1-84908-907-4.
  16. ^ "Arms of the Chosin Few". Americanrifleman.org. Retrieved 2011-11-23. 
  17. ^ Hall, Donald L. (March 1952). "An effectiveness study of the infantry rifle. Report No. 593" (PDF). Maryland: Ballistic Research Laboratories (published 29 March 1973). 
  18. ^ Fanaticism And Conflict In The Modern Age, by Matthew Hughes & Gaynor Johnson, Frank Cass & Co, 2005
  19. ^ "An Attempt To Explain Japanese War Crimes". Pacificwar.org.au. Retrieved 2012-08-23. 
  20. ^ "South to the Naktong - North to the Yalu". History.army.mil. Retrieved 2012-08-23. 
  21. ^ "HyperWar: The Big 'L'-American Logistics in World War II". Ibiblio.org. Retrieved 2011-12-24. 
  22. ^ "The Logistics of Invasion". Almc.army.mil. Archived from the original on 2015-06-22. Retrieved 2011-11-23. 
  23. ^ a b c d Harrison (NRA Technical Staff), E. H. (Col.) (June 1957). "New Service Rifle" (PDF). Archived from the original (PDF) on 2015-11-07. 
  24. ^ Williams, Anthony G. (3 February 2012). "Assault Rifles And Their Ammunition: History and Prospects". Quarry.nildram.co.uk. Archived from the original on 2014-06-02. Retrieved 2011-11-23. 
  25. ^ a b c Pikula, pp. 36, 38
  26. ^ Pikula, Major Sam. The ArmaLite AR-10. Regnum Fund Press, 1998. ISBN 9986-494-38-9. pp. 27-29
  27. ^ Pikula, Sam (Major), The ArmaLite AR-10, p. 38: Later changed to titanium.
  28. ^ Pikula, pp. 27-30
  29. ^ Lewis, Jack (1963). "The M-14: Boon or Blunder". Gun World. 3 (4). 
  30. ^ Pikula, pp. 39-40
  31. ^ a b c d e f g h i Bruce, Robert. "M14 vs. M16 in Vietnam". Small Arms Review. 
  32. ^ Jane's International Defense Review. Jane's Information Group. 36: 43. 2003. The M14 is basically an improved M1 with a modified gas system and detachable 20-round magazine.  Missing or empty |title= (help)
  33. ^ "M14 7.62mm Rifle". Globalsecurity.org. 1945-09-20. Retrieved 2011-11-23. 
  34. ^ Emerson, Lee (10 October 2006). "M14 Rifle History and Development" (PDF). 
  35. ^ Rottman, Gordon (2002). Green Beret in Vietnam: 1957-73. Osprey Publishing. p. 41. 
  36. ^ Hutton, Robert (ed.), The .223, Guns & Ammo Annual Edition, 1971.
  37. ^ Ezell, Edward Clinton (1983). Small Arms of the World. New York: Stackpole Books. pp. 46–47. ISBN 978-0-88029-601-4. 
  38. ^ http://www.forgottenweapons.com/wp-content/uploads/2014/07/1959-Rifle-Squad-Armed-with-a-Light-Weight-High-Velocity-Rifle.pdf Rifle Squad Armed with a Light Weight High Velocity Rifle. U.S. Army Combat Experimentation Center. Fort Ord. Californaia. 24 Jun 1959
  39. ^ http://www.forgottenweapons.com/wp-content/uploads/2014/07/1959-Rifle-Squad-Armed-with-a-Light-Weight-High-Velocity-Rifle.pdf Rifle Squad Armed with a Light Weight High Velocity Rifle. U.S. Army Combat Experimentation Center. Fort Ord. Californaia. 24 Jun 1959
  40. ^ Dockery, Kevin (2007). Future Weapons. Penguin. p. 56. ISBN 9780425217504. 
  41. ^ Zimba, Jeff W. "Colt ArmaLite AR-15 Rifle #000106 The Coconut Rifle". smallarmsreview.com. Retrieved 2017-11-13. 
  42. ^ "An Improved Battlesight Zero for the M4 Carbine and M16A2 Rifle". Retrieved 2007-09-11. 
  43. ^ "TM 9-1005-319-10 (2010) - Operator's Manual for Rifle, 5.56 MM, M16A2/M16A3/M4 (Battlesight Zero pages 48-55)" (PDF). Retrieved 2014-06-03. 
  44. ^ "An Improved Battlesight Zero for the M4 Carbine and M16A2 Rifle". Retrieved 2007-09-11. 
  45. ^ "TM 9-1005-319-10 (2010) - Operator's Manual for Rifle, 5.56 MM, M16A2/M16A3/M4 (Battlesight Zero pages 48-55)" (PDF). Retrieved 2014-06-03. 
  46. ^ a b c d e f g Rose, Alexander (2009). American Rifle: A Biography. Random House Publishing Group. ISBN 9780553384383. 
  47. ^ "REPORT OF TASK NO. 13A. TEST OF ARMALITE RIFLE. AR-15 (U)" (PDF). RESEARCH & DEVELOPMENT FIELD UNIT. Advanced Research Projects Agency. 31 July 1962. 
  48. ^ "REPORT OF TASK NO. 13A. TEST OF ARMALITE RIFLE. AR-15 (U)" (PDF). RESEARCH & DEVELOPMENT FIELD UNIT. Advanced Research Projects Agency. 31 July 1962. 
  49. ^ "Martin L. Fackler, Wounding patterns of military rifle bullets" https://www.ar15.com/ammo/project/Fackler_Articles/wounding_patterns_military_rifles.pdf
  50. ^ "REPORT OF TASK NO. 13A. TEST OF ARMALITE RIFLE. AR-15 (U)" (PDF). RESEARCH & DEVELOPMENT FIELD UNIT. Advanced Research Projects Agency. 31 July 1962. 
  51. ^ Sweeney, Patrick (28 February 2011). Modern Law Enforcement Weapons & Tactics, 3rd Edition. Iola, Wisconsin: Krause Publications. p. 240. ISBN 978-1-4402-2684-7. Retrieved 6 June 2013. 
  52. ^ Ezell, Edward Clinton (1983). Small Arms of the World. New York: Stackpole Books. pp. 46–47. ISBN 978-0-88029-601-4. 
  53. ^ a b Thomas P. Ehrhart Increasing Small Arms Lethality in Afghanistan: Taking Back the Infantry Half-Kilometer
  54. ^ Bartocci, Christopher R. (2011-07-20). "Feeding the Modern Semi-Automatic Rifle". Americanrifleman.org. Retrieved 2012-08-23. 
  55. ^ a b c Ezell, Edward Clinton (1983). Small Arms of the World. New York: Stackpole Books. pp. 746–762. ISBN 978-0-88029-601-4. 
  56. ^ "Archived copy" (PDF). Archived from the original (PDF) on 2012-05-17. Retrieved 2014-02-12.  ARMALITE TECHNICAL NOTE 54: DIRECT IMPINGEMENT VERSUS PISTON DRIVE
  57. ^ Pages 744–759 "Small Arms of the World" 12th Revised Edition by Edward Clinton Ezell.
  58. ^ https://www.forgottenweapons.com/explaining-the-ar-safety-lever-design-video/