Tag Archive for 'aircraft machine gun'

30 mm Mk. 101 (Rheinmetall): Aircraft Machine Gun

30 mm Mk. 101 (Rheinmetall): Aircraft Machine Gun

The Mk. 101, also known as the M.G. 101, is a scaled-up version of the Solothurn S-18-1000, 20 mm antitank rifle used by the Swiss, Italians, Hungarians, and to some small extent the Germans. It is Germany’s first attempt to put a gun of over 20 mm caliber in an airplane. It was designed to be used principally for antitank work, but a high-explosive round is furnished for antipersonnel use.

It has been used mostly on the Russian front in the Heinkel 129, a heavily armored plane especially designed for ground attack. Neither the Mk. 101 nor the plane has worked out too well, and a new 23 mm Mauser cannon and two new 30 mm guns, the Mk. 107 and Mk. 108, are now coming into use in the German Air Force.

In the Heinkel 129, the Mk. 101 was fixed to a mount that could be attached to the bomb racks under the fuselage when the plane was sent on a tank-hunting or other special mission. The gun is a recoil-operated, magazine- or drum-fed, semi- or full-automatic, air-cooled weapon. It does not have a particularly high velocity; the armor-piercing, high-explosive tracer ammunition gives a velocity of 2,330 f/s, and the light armor-piercing tungsten carbide-cored round, 2,800 f/s.


Caliber         30 mm (1.18 ins.)
Operation Recoil
Feed system 10- or 20-round box magazine; 30-round drum
Weight 394 lb. (without mount)
Length 96 ins. (overall)

German: p. 253

20 mm M.G. 151/20 (Mauser): Aircraft Machine Gun

20 mm M.G. 151/20 (Mauser): Aircraft Machine Gun
The M.G. 151/20 mm and M.G. 151/15 mm (Mauser) were designed and built by the famous Mauser factory. The M.G. 151/20 is a fixed aircraft cannon, recoil-operated and belt-fed, using a disintegrating metallic link belt. It was manufactured also in a 15 mm form. Although the receiver group and the recoiling portions are not identical, the superficial appearance of the two guns is very similar.

Two of these guns are mounted in each of the Focke-Wulf FW 190 types of planes. In this installation, they are synchronized, firing through the propeller arc. They are installed in the wing roots about 12 inches out from the engine cowling with the barrels protruding about 2 feet beyond the leading edge.

This gun is electrically cocked and fired, and electric detonation of the cartridge has been adopted in order to facilitate interruption when it is used as a synchronized gun. A longer-barreled version with mechanical detonation is used when the gun is mounted to fire through the propeller hub as in the ME-109.

In the version mounted in the fuselage, the feeding device has a capacity of 50 rounds, but more rounds are usually carried for each gun when it is wing mounted. A streamlined container holds the gun and the belted ammunition in newer installations.

The following types of ammunition are used in the 20 mm version: H.E. with S.D. fuze; H.E.I./T. with S.D. fuze; A.P.I., A.P.H.E., and two different H.E.I. (S.D. fuze) rounds.


Caliber         20 mm (.787 in.)
Weight including electric control 93 1/2 lb.
Weight of barrel 22 lb., 14 oz.
Overall length 69 1/2 ins.
Length of barrel 43 1/2 ins.
Principle of operation Short recoil, no muzzle recoil booster, rotating bolt head
Cooling system Air
Feeding device Disintegrating metallic link belt
Capacity of belt 50 rds. and multiples thereof
Muzzle velocity (H.E.) 2,656 f/s
Rate of fire 780 r.p.m.
Ammunition used H.E. with S.D. fuze; H.E.I./T. with S.D. fuze; A.P.I.; A.P.H.E.; and two different H.E.I. (S.D. fuze) rounds.

German: p. 252

20 mm M.G. F.F.M. (Oerlikon): Aircraft Machine Gun

20 mm M.G. F.F.M. (Oerlikon): Aircraft Machine Gun

This flexible 20 mm aircraft machine gun, Oerlikon M.G. F.F., is the German Air Force version of the Swiss Oerlikon 20 mm machine gun.

The weapon is a blowback, inertia-operated, air-cooled machine gun for fixed or flexible mounts. It fires from an open bolt and has an electrically operated trigger mechanism. The cartridge-counting mechanism is also electrically operated. It has a pneumatic charging mechanism to retract the bolt for the first shot.

Some minor modifications of the Swiss version of this machine gun have been introduced. It is chambered to fit the short German 20 mm round, and the travel of the recoiling parts has been redesigned to conform. The barrel has been shortened and the gun lightened considerably. It has been in use in this form without material alteration since the beginning of the war.

The gun was originally intended as a fixed weapon and was termed the M.G. F.F. A later type, the F.F.M., is mechanically the same but in some cases is provided with a cooling cowling and a hand firing device for use as a free gun. It is used both as a flexible and a fixed gun.


Caliber         20 mm
Weight 76 1/2 lb.
Length 57 ins.
Feed Drum—60 rd. capacity
Length of barrel 32 1/4 ins.
Cooling Air
Operation Blowback (inertia) with solenoid trigger
Fire Automatic only
Rate of fire 450 to 500 rds./min.—cyclic

German: p. 251

13 mm M.G. 131: Fixed or Flexible Aircraft Machine Gun

13 mm M.G. 131: Fixed or Flexible Aircraft Machine Gun

The German flexible aircraft machine gun, M.G. 131, 13 mm, is the Nazi tactical counterpart of the U.S. Browning, cal. .50, M2. Action is a Solothurn type—that is, the locking cam on a rotating bolt head engages a cylindrical locking collar to lock the action for firing. It is fed by a metallic disintegrating-link belt.

The M.G. 131 is used singly and in twin-mounted versions in hand-operated mounts and power-operated turrets in many German bombers. The recoil operation is assisted by a muzzle recoil booster. It is unusual in that the cartridges are ignited electrically instead of by a mechanically operated firing pin.

It is a recoil-operated, gas-assisted, belt-fed, air-cooled, automatic weapon that is coming into more extensive use in the German Air Force.


Caliber         13 mm (.512 in.)
Weight 40 lb.
Length 46 ins.
Rate of fire 900 rds./min.—cyclic
Muzzle velocity 2,370 f/s
Sights Refractor type on mount
Ammunition 13 mm Solothurn types—A. P., T; H. E., T

German: p. 222

7.92 mm M.G. 81: Flexible Aircraft Machine Gun

7.92 mm M.G. 81: Flexible Aircraft Machine Gun - Luftwaffe WW2

The German Aircraft Machine Gun, M.G. 81, 7.92 mm, is a Mauser designed air-cooled, belt-fed, recoil-operated (gas assisted) weapon which fires from an open bolt. The weapon is light and easily manufactured and is now used in place of the German M.G. 15 in many German aircraft. It is a flexibly mounted gun and serves as an observer’s weapon.

A “Solothurn type” bolt head is rotated by cams and locked to the barrel by an interrupted thread. It appears to be a speeded-up type of the light machine gun, M.G. 34. The higher rate of fire is achieved by a powerful buffer spring fitted into the body, as well as by general lengthening of all parts, and some redesign. The recoil operation is assisted by a nuzzle booster. The barrel is unusually short, being only 183 inches long. A push-type safety catch is located in the trigger guard just forward of the trigger. This can be moved only when the gun is cocked.

The weapon is fired only at full-automatic fire. The method of feeding is by a disintegrating-link belt through the feed block. A barrel casing made of perforated sheet metal encloses the barrel and fits into a sleeve which screws into the front of the body. The weapon has a muzzle booster which screws onto the barrel housing. This weapon is made and used in a dual mount with single trigger operation for both mounts.


Caliber        7.92 mm. (.312 in.)
Weight 13 lb., 14 oz.
Length 35 ins.
Length of barrel 18.75 ins.
Operation Recoil, gas assisted
Fire Automatic only
Muzzle velocity* 2,500-3,000 f/s
Rate of fire 1,200 to 1.500 rds./min.
Ammunition All 7.92 mm Mauser types

*Muzzle velocity varies according to ammunition used.

German: p. 221

7.92 mm M.G. 17: Fixed Aircraft Machine Gun

7.92 mm M.G. 17: German WW2 Fixed Aircraft Machine Gun

The German 7.92 mm aircraft machine gun, M.G. 17, is an air-cooled, recoil-operated, gas-assisted, belt-fed, pneumatically charged, fixed weapon fired electrically by solenoid. It differs from the M.G. 15 in that it fires from a closed bolt. Three types of links have been found used with the belt feed of this weapon: sectionally disintegrating, fully disintegrating, and nondisintegrating. The gun, which has a fixed mount, is well constructed with excellent machining throughout.

All parts are of steel with the exception of the rear buffer housing which is of cast dural with an anodized finish. The rest of the gun is covered with a good parkerized finish. The barrel is connected to the barrel extension by an interrupted thread type fastening. The bolt is of the Solothurn rotating type and operates on small steel rollers.

The M.G. 17 is used in many types of German aircraft, and is stationed in various positions so that it may be fired unsynchronized or synchronized through the propellor arc by solenoid.


Caliber         7.92 mm (.312 in.)
Weight 27 lb., 11 oz.
Length 47 3/4 ins.
Length of barrel 23 5/8 ins.
Muzzle velocity 2,800 f/s
Rate of fire 1,000 rds./min. (synchronized)
1,100 rds./min. (unsynchronized)
Operation Recoil, gas assisted
Fire Automatic only
Rifling 37° uniform right-hand twist, 1 turn in 10 ins.

German: p. 220