i play counter strike but i dont understand what is the difference between sub-machine gun and machine gun?

Answer 1

Sub-machine guns are usually small, fully automatic, or have a selector switch to go between full and semi-auto. Most of them fire ammunition developed for use in handguns such as the .45 A.C.P. An example of an SMG is the Heckler & Koch MP5. There are no submachine guns that are semi-automatic only.

Assult rifles are usually larger, and most of them fire cartridges developed for use in rifles such as the 5.56mm (.223 Rem). They are either fully automatic, or have a selector switch to select semi or full auto. An example of an assult rifle is a Colt M4 Carbine. There are no assult rifles that are semi-automatic only.

Answer 2

Just browsed and saw this older question.

A sub(sonic) weapon is one that fires ammunition that flies slower than about 1260 feet per second, or the speed of sound at sea level.

A submachine gun is of course, still very lethal but has a limited range due to the relatively slower bullet and quick drop over long distances. It has a noticeable decrease in muzzle noise since along with the expected 'pop' of firing, there is no loud crack associated with the round flying above the sound barrier.

Answer 3

Sub-machine guns are usually small, fully automatic, or have a selector switch to go between full and semi-auto. Assault rifles are usually larger than sub-machine guns