Jump to content
 







Main menu
   


Navigation  



Main page
Contents
Current events
Random article
About Wikipedia
Contact us
Donate
 




Contribute  



Help
Learn to edit
Community portal
Recent changes
Upload file
 








Search  

































Create account

Log in
 









Create account
 Log in
 




Pages for logged out editors learn more  



Contributions
Talk
 



















Contents

   



(Top)
 


1 Design  





2 Feeding mechanism  





3 Firing cycle  





4 US Army Air Forces  





5 US Navy  





6 Soviet Air Forces  





7 US-built contemporaries and successors  





8 See also  



8.1  Weapons of comparable role, performance and era  







9 Notes  





10 References  





11 External links  














M4 autocannon






العربية

Polski
 

Edit links
 









Article
Talk
 

















Read
Edit
View history
 








Tools
   


Actions  



Read
Edit
View history
 




General  



What links here
Related changes
Upload file
Special pages
Permanent link
Page information
Cite this page
Get shortened URL
Download QR code
Wikidata item
 




Print/export  



Download as PDF
Printable version
 




In other projects  



Wikimedia Commons
 
















Appearance
   

 






From Wikipedia, the free encyclopedia
 


37 mm Automatic Gun, M4
TypeAutocannon
Place of originUnited States
Service history
In service1942–1945
Used byUnited States
Soviet Union
WarsWorld War II
Production history
DesignerJohn Browning
Designed1921–1938
ManufacturerColt
Produced1939
VariantsM9, M10
Specifications
Mass213 lb (97 kg)
Length89.5 in (2.27 m)

Shell37×145mmR
Caliber37 mm (1.46 in)
Actionrecoil operation
Recoil9+58 in (245 mm)
Rate of fire150 rpm
Muzzle velocity2,000 ft/s (610 m/s)
Feed system30-round magazine

The 37 mm Automatic Gun, M4, known as the T9 during development, was a 37 mm (1.46 in) recoil-operated autocannon designed by Browning Arms Company and entered service in 1942.[1] The M4 and its variants would primarily be manufactured by Colt's Manufacturing Company and Oldsmobile (under-contract by Colt) and is therefore sometimes referred to as the "Colt M4" or "Oldsmobile M4."[2] It was primarily mounted in the Bell P-39 Airacobra and P-63 Kingcobra, with the U.S. Navy also utilizing it on many PT boats.

Design

[edit]
An M4 gun displayed at the Finnish Air Force Museum, 2012

Designed primarily as an anti-aircraft weapon, the gun had a muzzle velocity of 2,000 ft/s (610 m/s) and a cyclic rate of 150 rounds per minute. It was normally loaded with high-explosive shells, but could also be loaded with the M80 armor-piercing shell, which could penetrate 1 inch (25 mm) of armor plate at 500 yd (460 m). It was magazine-fed and could be fired manually or by remote control through a solenoid mounted on the rear of the gun.

Recoil and counter-recoil were controlled hydraulically by means of a piston and spring combination connected to the recoiling mechanism and operating in an oil-filled recuperator cylinder mounted to the stationary trunnion block assembly. The recoiling mechanism of the gun included the tube and tube extension, recuperator piston and piston rod, lock frame assembly, driving spring assemblies, and the breechblock assembly. The nonrecoiling parts included the trunnion block group, the feed box and feeding mechanism, the recuperator cylinder and bushing, the back plate group, and the manual charger assembly.

Feeding mechanism

[edit]

As the gun was originally designed, ammunition could be fed by a 5-round clip, a 15-round link belt, or a non-disintegrating 30-round endless belt magazine. The 30-round endless belt version was used exclusively in production. The M4 gun fed only from the left.

The 30-round endless belt magazine was given the designation M6; it had an oval-shaped framework (nicknamed a "horsecollar magazine" from its shape) providing a track for the endless belt.[3][4][5]

Firing cycle

[edit]

Initial loading and cocking of the gun were accomplished manually. A safety feature incorporated in the design of the trigger mechanism prevented firing the round until the breech-block assembly was in the battery position.

The breech was locked and unlocked by recoil action which brings the operating level guide pins against cams to raise and lower the breechblock. The function of the breechblock was to assist in the final chambering of the round, close the breech, and actuate the trigger trip. It also provided a mounting for the firing pin.

The lock frame was retracted by recoil action during automatic firing and is forced forward by the driving springs. The major function of the lock frame assembly was to force the cartridge into the chamber, actuate the breech block, fire the round by means of the hammer striking the firing pin, extract the cartridge case from the chamber, and operate the ejector.

The back plate assembly, by absorbing the energy of the lock frame, reduced the shock against the carrier pin as the lock frame was hatched to the rear.

The driving spring assemblies held the lock frame against the carrier dog until the carrier was released by carrier catch which was pivoted by the incoming round. The springs then drove the lock frame assembly forward to operate the ejector, chamber the round and raise the breech block.

Initial extraction occurred during recoil. Extraction, ejection, feeding and loading were accomplished during counter-recoil. If the trigger was held in the firing position, the gun would continue to fire automatically until the magazine was empty.

US Army Air Forces

[edit]
P-39Q Airacobra weapons bay showing the M4 cannon's "horse-collar" drum magazine

The 37 mm cannon was disliked by pilots for its low muzzle velocity, resulting in more pronounced drop than other contemporary weapons.[citation needed]

The only standard aircraft armed with the M4 to see service were the Bell P-39 Airacobra and the derivative P-63 Kingcobra. It was used as a limited standard aircraft in North Africa campaign and the Pacific theater by the USAAF and Allied air forces.

Some YP-38s, the prototype model of the Lockheed P-38 Lightning, mounted a single M4 before the armament scheme was finalized.[6] Production Lightning models would replace the M4 with the AN/M2 20 mm cannon.

The experimental XP-58 "Chain Lightning" was a larger, more heavily armed version of the P-38 Lightning equipped with quadruple M4 cannons instead of M2 heavy machine guns in its nose. Its original purpose (like the German Messerschmitt Bf 110) was to destroy formations of bombers, but it was later re-envisioned as a ground-attack plane. The more pronounced ballistic trajectory was unfamiliar for American pilots, and the four M4s were replaced with a single 75mm M5 cannon and a pair of .50 caliber heavy machine guns.

The first US jet, the Bell P-59 Airacomet, saw two out of three YP-59s and the single XP-59 armed with twin nose-mounted M10 autocannons, a slightly updated and refined version of the M4. Production-model P-59s mounted a single M10 cannon in the nose bearing 45 shells, along with three M2 .50 caliber machine guns bearing 200 rounds each.

US Navy

[edit]
Restored PT658 on the Columbia River, October 2014. Note: M4 37 mm (1.46 in) automatic cannon mounted on the bow.
M4 at the National Museum of the United States Air Force

The M4 37 mm (1.46 in) automatic cannon was mounted on numerous U.S. Navy PT boats as deck guns, beginning with the Solomon Islands campaign. Primary targets were the landing barges being used to move supplies down the island chain at night. At first, they were cannibalized from crashed P-39s at Henderson Field, and due to their success as an anti-barge weapon were used for the rest of the war. The M4s were initially mounted on a simple pedestal mount (often built at the front lines) with the standard horseshoe endless-belt feed being used. Later, an improved pedestal mount was designed for original equipment mountings on the boats. Handgrips of several configurations were used with various sights being tried. Most PT boat gunners used tracers to sight the fall of their shot. Beginning in 1944, the M9 model 37 mm (1.46 in) cannon was installed at the builders' boatyard as standard equipment.

Soviet Air Forces

[edit]

During World War II the United States supplied the Soviet Air Forces with the M4-equipped P-39 Airacobra and P-63 King Cobra. The U.S did not supply M80 armor-piercing rounds for these Lend-Lease aircraft—instead, the Soviets received 1,232,991 M54 high-explosive rounds. The M4 was sometimes employed against soft ground targets on the Eastern Front but was primarily used in air-to-air combat, in which role it was highly effective. The Soviets did not use the P-39 for tank-busting.[7] Soviet pilots appreciated the M4's reliability but complained of its low rate of fire (three rounds per second) and small magazine size (30 rounds).[8]

US-built contemporaries and successors

[edit]

See also

[edit]

Weapons of comparable role, performance and era

[edit]

Notes

[edit]
  1. ^ Bishop, Chris (2002). The Encyclopedia of Weapons of World War II. New York: Friedman/Fairfax Publishers. p. 161. ISBN 1-58663-762-2.
  • ^ https://ss.sites.mtu.edu/mhugl/2019/10/12/oldsmobile-plants-involvement-in-world-war-two-2/
  • ^ Emmanuel Gustin; Anthony G. Williams (2003). Flying Guns: The Development of Aircraft Guns, Ammunition and Installations, 1933-45. Airlife. p. 153. ISBN 978-1-84037-227-4.
  • ^ Ian V. Hogg (2001). The American Arsenal: The World War II Official Standard Ordnance Catalog of Small Arms, Tanks, Armored Cars, Artillery, Antiaircraft Guns, Ammunition, Grenades, Mines, Etc. Greenhill Books. p. 217. ISBN 978-1-85367-470-9.
  • ^ Gordon Rottman (2011). US Patrol Torpedo Boats: World War II. Osprey Publishing. p. 22. ISBN 978-1-78096-208-5.
  • ^ Caidin, Martin (2001). "YP-38 37mm". Fork-Tailed Devil: The P-38. USA: J. Boylston, Publishers. ISBN 9780743413183. Archived from the original on 30 November 2021. Retrieved 30 November 2021. …one 37mm cannon…
  • ^ Loza, Dmitriĭ Fedorovich (2002). Attack of the Airacobras: Soviet Aces, American P-39's and the Air War against Germany. University Press of Kansas. p. 359. ISBN 0-7006-1140-1.
  • ^ Drabkin, Artem. The Red Air Force at War: Barbarossa and the Retreat to Moscow – Recollections of Fighter Pilots on the Eastern Front. Barnsley, South Yorkshire, UK: Pen & Sword Military, 2007, p. 133. ISBN 1-84415-563-3.
  • ^ a b George Chinn 1951, The Machine Gun: Development During World War II and Korean Conflict by the United States and their Allies of Full Automatic Machine Gun Systems and High Rate of Fire Power Driven Cannon, Volume III, Parts VIII and IX., p. 352
  • ^ a b Anthony G. Williams (2002). Rapid Fire: The Development of Automatic Cannon, Heavy Machine-Guns and Their Ammunition for Armies, Navies and Air Forces. Airlife. pp. 155–156. ISBN 978-1-84037-435-3.
  • References

    [edit]
    [edit]
    Retrieved from "https://en.wikipedia.org/w/index.php?title=M4_autocannon&oldid=1224817903"

    Categories: 
    37 mm artillery
    Aircraft guns
    Autocannon
    Hidden categories: 
    Articles with short description
    Short description is different from Wikidata
    Use dmy dates from June 2017
    Articles needing additional references from June 2016
    All articles needing additional references
    All articles with unsourced statements
    Articles with unsourced statements from January 2023
    Commons category link is on Wikidata
     



    This page was last edited on 20 May 2024, at 17:00 (UTC).

    Text is available under the Creative Commons Attribution-ShareAlike License 4.0; additional terms may apply. By using this site, you agree to the Terms of Use and Privacy Policy. Wikipedia® is a registered trademark of the Wikimedia Foundation, Inc., a non-profit organization.



    Privacy policy

    About Wikipedia

    Disclaimers

    Contact Wikipedia

    Code of Conduct

    Developers

    Statistics

    Cookie statement

    Mobile view



    Wikimedia Foundation
    Powered by MediaWiki