Browning machine guns (BMGs) are standard weapons used throughout the Navy. The .50-caliber BMG issued to naval activities is designated the M2. The weapon is available with two types of barrels. An aluminum alloy "light" barrel is used for the aircraft version of the .50-caliber BMG, M2. A "heavy" barrel (HB) is issued for ship and surface craft use. Our discussion centers around the .50-caliber BMG, M2HB (fig. 13-33).

GENERAL DESCRIPTION

The .50-caliber BMG is a belt-fed, crew-served, recoil-operated, air-cooled weapon. It can be set for automatic and semiautomatic fire. The .50-caliber BMG does not have any positive safeties.

Ammunition is supplied to the receiver (ammunition feedway) of the gun by a disintegrating metallic link belt. The BMG is capable of alternate feed. Normally, the gun is fed from its left side; but by repositioning certain component parts, the belt may be fed from the right side.

One person can operate the .50-caliber BMG. However, two people, the gunner and assistant gunner, are normally used. The gunner actually fires the weapon.

Figure 13-34.-The 30-caliber BMG on an M3 tripod mount.

The assistant gunner helps to load and reload the ammunition into the receiver. Other personnel- ammunition bearers-can be used to keep the assistant gunner supplied. Speed, skill, and teamwork are important.

The force for recoil is finished by the expanding gases of the fired cartridges. The recoil operation is controlled by various springs, cams, and levers within the gun.

Most of the barrel and receiver is exposed to the air to cool the .50 caliber BMG. Perforations (holes) in the barrel support allow air to circulate around the breech end of the barrel. A heavy barrel (HB) is used to retard, or slow down, early overheating.

The .50-caliber BMG has a leaf type of rear sight. It is graduated in both meters and mils for ranges from 100 to 2600 meters and from 0 to 62 mils. A windage knob permits deflection changes of 5 mils right or left of the center. The front sight is a semifixed blade type with a cover. Because of its size and weight, the .50-caliber BMG usually needs some type of mounting support. Figure 13-34 shows the M3 tripod mount arrangement. Other devices or stands may also be used. The primary reason for mounting the weapon is to increase its firing accuracy.

The main characteristics of the .50-caliber BMG are listed below.

Weight of receiver group . . 60 pounds

Figure 3-35.-Major component groups and assemblies.