Light Machine Guns/Automatic Rifles. The light machine gun (LMG) classification generally includes.22 to .250 caliber (5.45mm to 6mm) automatic weapons. An LMG typically weighs between 15 and 30 pounds, complete. An LMG is normally manned by a crew of one or two individuals depending on the accessories being used. Neither a tripod nor a spare barrel is normally used with an LMG when it is manned by a single individual. Bullet weights for LMGs normally range from 45 to 72 grains. They are optimally employed against exposed and lightly protected personnel at ranges less than 1,000 meters. In this category,
Medium Machine Guns. This medium machine gun (MMG) classification generally includes.264 to .33 caliber (6.5mm to 8mm) automatic weapons. Typical MMG weights are 25 rounds or more when loaded with 50 rounds of ammunition. Remaining ammunition, ground tripod, spare barrel, and other accessories can add another 25 pounds or more to the overall weight of MMG systems. The MMG is generally employed by a crew of three. A MMG generally uses bullets that weigh between 140 and 220 grains. Optimally, they are employed against personnel and light materials ( e.g., motor vehicles) at ranges of 1500 meters or less.
Heavy Machine Guns. The heavy machine gun (HMG) classification generally includes .50 caliber or larger (12.7mm to 15mm) automatic weapons. The system weight of a heavy machine gun is substantial. In a ready to fire configuration using a ground tripod, an HMG without ammunition can weigh more than 125 pounds. An HMG is normally manned by a crew of four or more personnel (although a crew of three may be sufficient if motor vehicles or draft animals are employed for transportation over distance). The common bullet weight of an HMG is 700 grains or larger. HMGs are primarily employed against field fortifications, vehicles, and aircraft. They are generally effective against these types of targets at ranges of 1,000 meters or greater.