MG FF cannon

MG FF
A restored MG FF cannon.
Type	Aircraft Cannon
Place of origin	Germany
Service history
Wars	World War II
Production history
Manufacturer	Ikaria
Specifications
Weight	26.3 kg
Length	1.37 m
Shell	20 x 80 mm
Caliber	20 mm
Rate of fire	520-540 rpm
Muzzle velocity	585, 600 or 700 m/s

The MG FF was a drum-fed, 20 mm aircraft autocannon, developed in 1936 by Ikaria Werke Berlin of Germany. It was a derivative of the Swiss Oerlikon FF F cannon, itself a development of the German World War I Becker 20 mm cannon, and was designed to be used in fixed or flexible mountings, as both an offensive and a defensive weapon. It saw widespread use in those roles by the German Luftwaffe, particularly during the early stages of World War II, although from 1941 onwards it was gradually replaced by the 20 mm MG 151/20.

Compared to rival designs, such as the Hispano-Suiza HS.404 - which had been developed from the larger Oerlikon FF S - the MG FF had some disadvantages, such as low rate of fire and low muzzle velocity, as well as limited ammunition storage in its drums. On the other hand, it was much lighter and shorter. Wing installation on the Messerschmitt Bf 109 and Focke-Wulf Fw 190 fighters was not easy, as the drum required substantial space, and as a consequence the ammunition storage was initially reduced to 60 shells per drum. An ammunition drum of 90-round nominal capacity was developed for the Fw 190 A-5, and retrofitted to some earlier variants. There were also experiments with belt feedings.

The MG FF was adapted to fire a new type of high-capacity, high explosive mine shell, called Minengeschoss that featured a projectile with thinner walls that allowed increased explosive charge. This projectile was lighter and generated less recoil than earlier projectiles requiring a modification of the recoil mechanism. With this modification it could fire the new mine shell, but accidentally using the heavier MG FF ammo could damage the gun. The now-called MG FF/M was introduced with the Bf 109 E-4 and Bf 110 C-4 in Summer 1940.

The MG FF and FF/M saw widespread use in fighters such as the Bf 109 E-3 to F-1, Bf 110 C to F, and Fw 190 A-1 to A-5. The Fw 190 was typically fitted with an inboard pair of MG 151 and an outboard pair of MG FF, although the MG FF were sometimes removed in the field in order to save weight. The cannon was also fitted to bombers such as the Do 217, Ju 88, He 111, Do 17, as well as many other aircraft. Although the MG FF was often replaced with the 20 mm MG 151/20 from 1941 onwards, it saw a come-back in 1943 as the primary Schräge Musik gun in the Bf 110 night fighters, as it perfectly fitted into the rear cockpit.

The MG FF fired a 134 g projectile with a muzzle velocity of some 600 m/s and a rate of fire of about 520 rounds per minute. The MG FF/M fired a 90 g HE/M (high explosive mine shell) projectile with a muzzle velocity of c. 700 m/s and a rate of fire of c. 540 rounds per minute. AP, HE and incendiary projectiles were also available (115 to 117 g projectiles, 585 m/s, c. 520 rpm) because the mine-shot was not capable of holding incendiary or tracer parts.

File:Me 110 SM.jpg

MG FF/M as Schräge Musik in the Bf 110.

Technical data

• Weight : 26.3 kg
• Length : 1.37 m
• Muzzle Velocity : 600 m/s (MG FF), 585 m/s (FF/M with AP or HE), 700 m/s (MG FF/M with mine shell)
• Rate of Fire : 520 rpm (MG FF, FF/M with AP or HE), 540 rounds per minute (MG FF/M with mine-shot)
• Round types: armor piercing (AP), high explosive (HE), incendiary, all with or without tracer; high explosive mine-shot (HE(M)) (only MG FF/M)

20mm Gun Table

Name	Cartridge	Projectile weight	Rate of fire	Muzzle velocity	Gun weight
		(grams)	(rpm)	(m/s)	(kg)
France
HS.9	20 x 110RB	122	360-420	830	48
HS.404	20 x 110	130	700	880	60
Germany
MG FF	20 x 80RB	134	520	600	28
MG FF/M	20 x 80RB	92/115	540/520	700/585	28
MG 151/20	20 x 82	92/115	750 - 800	800/720	42
Japanese Army
Type 94 Flexible	20 x 99RB	127	380	675	43
Ho-1	20 x 125	144	400	805	45
Ho-3	20 x 125	144	400	805	45
Ho-5	20 x 94	96	750 - 850	715	37
Japanese Navy
Type 99-1	20 x 72RB	129	490	600	23
Type 99-2	20 x 101RB	128	490	750	34
Great Britain
Hispano Mk.II	20 x 110	130	600	880	50
Hispano Mk.V	20 x 110	130	750	840	42
USSR
ShVAK	20 x 99R	95	800	750 - 770	42
Berezin B-20	20 x 99R	95	800	750 - 770	25
VYa	23 x 152B	200	550	880	69
NS-23	23 x 115	200	550	690	37

See also

• List of firearms
• List of common World War II infantry weapons
• List of weapons of military aircraft of Germany during World War Two

External links

• Anthony G. Williams' "Cannon, Machine Guns and Ammunition"
• Emmanuel Gustin's WWII fighter gun performance tables