What is the difference between machine gun and sub machine gun?

Answer 1

A sub machine gun fires pistol ammunition. A light machine gun fires rifle ammunition and is usually fired using a support (unless you are Rambo).

Also, a submachine gun (SMG) is lightweight and is meant to be carried around. However, a light machine gun (LMG) has a stance and is meant to be placed at one spot, as is a sniper rifle, and the LMG stays there and waits for an enemy, as does the sniper rifle. An SMG is meant to be run around because of their high recoil, or kick; the closer you are to someone, the less effect the kick has. The LMG is a very heavy weapon, but it has low recoil; still, it makes a difference from a distance. You can put a foregrip on an LMG, as it's not practical for an SMG, although it can be done. The foregrip on the LMG puts the kick to a minimum, making it great for camping.

Sources: experience in war knowledge and Call of Duty gaming.

Answer 2

Machine guns fire a rifle round and are built for continuous firing from belts of ammo whereas sub-machine guns fire a pistol round from a magazine, short periods of fire.

Answer 3

Generally, a sub-machine gun fires a handgun round and a machine gun fires a rifle round.