The light machine gun is an automatic weapons class that is more powerful and accurate then submachine guns or even assault rifles. They have a long range and the fastest rate of fire of all the machine guns. Although an LMG is meant to be carried by one individual, they are very heavy, incapaciting the player from sprinting when using one.
There is a considerable number of light machine guns in the Grand Theft Auto series, including the MG, M249 and M-60, Some of the light machine guns are classified as heavy weapons in some of the GTA games. They are relative hard to find compared to the other machine guns, they can be bought in gun shops, carried by very high-level law enforcement, or found, just laying around the city.
Following is information about the Light Machine Guns available in the Grand Theft Auto World.
The MG is based on the PKM, is a 7.62 mm general-purpose machine gun designed in the Soviet Union. The bolt and carrier design are similar to the AK, as is the stripping procedure performed to remove those mechanisms from the gun for cleaning. It is a modernized, product-improved version of the PK weighing only 7.5 kg without ammunition.
THe M249 is based on the weapon of same name. It is gas operated and air-cooled. It has a quick-change barrel, allowing the gunner to rapidly replace an overheated or jammed barrel. A folding bipod is attached near the front of the gun, though an M192 LGM tripod is also available. It can be fed from both linked ammunition and STANAG magazines, like those used in the M16 and M4.
The M-60 is based on the weapon of same name. It is a belt-fed machine gun that fires the 7.62 mm NATO cartridge (.308 Winchester) commonly used in larger rifles. It is generally used as a crew-served weapon and operated by a team of two or three individuals and uses the M13 ammunition link, a change from the older M1 link system with which it was not compatible.
The Gusenberg Sweeper is based on the M1928A1 Thompson. It is an American submachine gun, invented by John T. Thompson in 1918, that became infamous during the Prohibition era. It had provisions for box and drum magazines. It had a Cutts compensator, cooling fins on the barrel, employed a delayed blowback action and its charging handle was on the top of the receiver.
Even though it is clearly a submachine gun, it is classed in the LMG class in GTA V, and shares ammunition with other LMGs.