M3M and M3P 12.7 mm Machine Gun

Type

12.7 mm machine gun.

 Development

The M3 series of heavy machine guns for airborne use was developed during the Second World War as a faster-firing version of the Browning M2. The original designs were started by J M Browning around 1918 and the first gun produced was the Browning Cal 0.50 Model in 1921, which was manufactured by Colt's Patent Fire Arms Company. Development continued between the First and Second World Wars and the gun was improved into the M2. This was found to be an extremely reliable weapon during the Second World War, so much so that production was shared by no fewer than nine manufacturers. In 1946, development of the M3 was complete and since then they have been produced worldwide under licence, including by Fabrique National (FN) Herstal of Belgium.
            FN Herstal has developed two airborne versions of the M3; the M3M and the M3P. The M3M was developed for use in helicopter doors with pintle mounts such as the FN MFP (Medium Floor Pintle) and the MEP (Medium External Pintle) and the Italian, Aerea DGP (Door Gunner Post). In this configuration the M3M can be used for suppressive fire against troop carriers, in landing zones and for protection against ground and air attack. The M3M pintle mountings are covered by separate entries in this section of Jane's Air-Launched Weapons. The M3P was developed for use in fixed positions and pods such as the FN HMP-250/-400 (Heavy Machine Gun Pod) and the RMP and RMP-RL integrated system in order to provide light aircraft and helicopters with a standoff range against well-defended targets. The HMP and the RMP/RMP-RL are covered under separate entries. Over the years there have been many improvements to the M3P including a flash suppressor, a device to prevent `cook-offs' and different barrel options. One of the most recent and important developments is the FN 169 Armour-Piercing Explosive Incendiary-type ammunition designed to penetrate the side armour of armoured personnel carriers.
            The M3M is cleared for use on many different types of helicopter throughout the world. The M3P, when mounted in the HMP-250/-400, has been cleared for use on the Alpha Jet, EMB-312 Tucano, Pilatus PC-7 and PC-9, Britten-Norman Defender and Epsilon aircraft and SA 342 Gazelle, SA 350 Ecureuil, Bell 206, 406 and 412, MD 520, BO 105, BK 117, Sikorsky S-76 and H-76, Westland Lynx and WS-70 helicopters. The M3P is also used in the Aerea Multi-Task Pod, the Avibras MS 10-21 gun pod, FFV Uni-Pod 0127, Lucas helicopter gun turret, Global Helicopter Technology CFD 5000 gun pod, and the twin gun pack under C-101 Aviojet. The M3P is also used in the US Army and US Marine Corps battlefield air defence system Avenger, where it is used as a co-axial, boresighted machine gun with Stinger missiles.

 Description

Both the M3M and M3P are single barrelled, have a single feed and use 12.7 mm-type ammunition. The M3M, which can be used on several types of pintle, is 1.67 m long and weighs 36.4 kg. It has a firing rate of 959 to 1,050 rds/min and can use any of the following range of ammunition either separately or in mixed belts as required: M33 ball, M17 tracer, APM8 armour-piercing, APIM8 armour-piercing and incendiary, APITM20 armour-piercing and incendiary and tracer, APEI armour-piercing explosive and incendiary and HEPI high-explosive armour-piercing and incendiary.
            The M3M is credited with a muzzle velocity of 880 m/s, an accurate range of 1,790 m and remains effective up to 3,000 m. The M3P is designed for fixed installations and includes a firing solenoid, flash suppressor, `cook-off' preventer, and different barrel options. It is 1.65 m long, weighs 29 to 35 kg depending on the barrel, and has a firing rate of 900 to 1,100 rds/min. The HMP 50 carries 250 rounds of ammunition for the M3P which can include any of the above used for the M3M. The FN 169 Armour-Piercing Explosive Incendiary-type ammunition, designed especially for the M3P, weighs 112 g and has a projectile weight of 43 g including the penetrator of heavy alloy, which is located just behind the explosive/incendiary filling that occupies the nose of the projectile. This projectile is designed to penetrate the side armour of armoured personnel carriers at a range of 700 m. The M3P is credited with a muzzle velocity of 850 to 920 m/s depending on munition used and an accurate range of 1,500 m.

 Operational status

The M3M and M3P heavy machine guns are currently in service with several countries. In 1998, it was reported that the UK was examining the M3M for possible fitment to Chinook HC Mk 2 and Lynx helicopters.

 Specifications

 M3M
Calibre: 12.7 mm
Number of barrels: 1
Length: 1.67 m
Weight: 36.4 kg
Rate of fire: 959-1,050 rds/min
Muzzle velocity: 880 m/s

 M3P
Calibre: 12.7 mm
Number of barrels: 1
Length: 1.65 m
Weight: 29-35 kg depending on barrel
Rate of fire: 900-1,100 rds/min
Muzzle velocity: 850-920 m/s depending on ammunition

 Contractor