AN/M2 (20 mm)

This page is about the aircraft cannon AN/M2 (20 mm). For the naval machine gun, see AN-M2 (12.7 mm). For other uses, see M2 (Disambiguation).

Description

The AN/M2 (20 mm) is the US made variant of the HS.404 (20 mm) autocannon produced by the French company Hispano-Suiza in the mid-1930s. This cannon was typically utilised on aircraft and was fitted to airframes such as the D.520, F6F-5N and the P-61C-1.

General info

Tell us about the tactical and technical characteristics of the cannon or machine gun.

Available ammunition

• Default: HEF-I · AP-T
• Universal: AP-T · AP-T · HEF-I · HEF-I
• Ground targets: AP-T · AP-T · AP-T · HEF-I
• Air targets: HEF-I · HEF-I · HEF-I · AP-T
• Stealth: HEF-I · HEF-I · HEF-I

Penetration statistics
Ammunition	Penetration @ 0° Angle of Attack (mm)
	10 m	100 m	500 m	1,000 m	1,500 m	2,000 m
AP-T	39	36	25	16	10	6
HEF-I	5	4	3	2	2	2

Shell details
Ammunition	Velocity (m/s)	Projectile mass (kg)	Fuse delay (m)	Fuse sensitivity (mm)	Explosive mass (TNT equivalent) (g)	Ricochet
						0%	50%	100%
AP-T	779	0.17	-	-	-	47°	60°	65°
HEF-I	868	0.13	0.2	0.1	16.34	79°	80°	81°

Comparison with analogues

The HEF-I ammunition's muzzle velocity & drop is very similar to the M2 Browning's 868 m/s. However, the AP-T shell is much slower than most other shell types (779 m/s), which is just below the MG151 Minengeschoß's velocity. So it would be better to use the stealth belts since they only contain HEF-I shells, which deal a lot of damage to aircraft.

Usage in battles

Describe the cannon/machine gun in the game - its distinctive features, tactics of usage against notable opponents. Please don't write a "guide" - do not impose a single point of view, but give the reader food for thought.

Pros and cons

Pros:

• Good explosive filler
• Reasonably good rate of fire of 600 RPM

Cons:

• Tends to jam a lot if fired continuously
• Quite inaccurate unless upgraded

History

Before World War II, the aircraft of different nations were armed with either rifle-calibre machine guns or heavy machine guns with rifle-calibre machine guns to supplement them. In the United States, the M2 Browning, which emerged from a World War I era development program, came to serve as the main armament of aircraft in both the US Army Air Corps and US Navy. However, overseas the Europeans were working on developing aircraft armed with more powerful explosive cannons. While the development of these weapons also began during World War I, the 1930s marked the period where the designing of cannon-armed fighters began in earnest. The United States was not one to fall behind and first developed the 37 mm M4 cannon for aircraft use. However, the gun suffered from a low muzzle velocity and short range. Therefore it was only used in service on the P-39 and P-63 interceptors before a replacement was sought.

The British Government would come to the aid of the United States in the search for a replacement when they requested the United States produce the 20 mm Hispano Mk.I under license. This cannon was itself a licensed version of the French Hispano 404 cannon. The British would ultimately not select the American-designed M1 cannons due to the fact they were unreliable. The problem was later found to stem from the use of a longer chamber as the 20 mm was seen as artillery by United States doctrine and built to looser tolerances. Jamming presented the additional problem of throwing the plane's aim due to the uneven recoil forces of having a single cannon firing. The United States Army Air Corps would adopt the M1, but the problems led to the later adoption of the 20 mm AN/M2. The AN/M2 differs primarily in terms of the dimensions and some of the receiver parts. The M2 uses receiver slides with a projection that fits into a receiver side slot and the slide is held in place by a cotter pin. The receiver is also .02 inches longer than the M1 gun.

The AN/M2 was planned to become a standardized armament for American aircraft during World War II. The conversion was set to begin once enough cannons and ammunition were available, but it would be too late during the war for the conversion to occur. As a result, the fighters of World War II were still chiefly armed with large numbers of M2 Browning machine guns. The AN/M2 would still see action but in special roles on interceptors such as the P-38 Lightning, night fighters such as the F6F-5N Hellcat, and P-61 Black Widow, and bombers such as the B-29 Superfortress and the SB2C Helldiver. It still saw use on a small number of fighters later in the war specifically with the F4U-1C Corsair used by the Marines at Okinawa.

After World War II, The United States Air Force which was the successor of the US Army Air Corps adopted the improved M3 Browning heavy machine gun as their main aircraft mounted weapon alongside unguided rockets such as the FFAR "Mighty Mouse" which would replace the AN/M2 in service. After the Korean War, however, the M24, a development of the AN/M2 was adopted into service. The AN/M2 would remain in service with the United States Navy and Marine Corps arming some hold-over designs that began development during World War II including the venerable Skyraider attack aircraft and their first carrier-based jet fighter, the F9F Panther along with the later F3D-1 Skyknight. It would find itself serving on these aircraft in the jet age alongside the improved M3 variant which would replace it in service. The Hispano-Suiza-based autocannons would be replaced in service by the end of the 1950s with the M39 replacing the M24 in the Air Force and Browning-Colt Mk12 replacing the M3 in the Navy and Marine Corps.

Media

Videos

Top 7 Autocannons discusses the AN/M2 (20 mm) at 05:11 - War Thunder Official Channel

See also

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• reference to the article about the variant of the cannon/machine gun;
• references to approximate analogues by other nations and research trees.

External links

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• topic on the official game forum;
• other literature.