Page "Rifle" Paragraph 4

Formerly, rifles only fired a single projectile with each squeeze of the trigger.

Modern rifles are capable of firing more than one round per trigger squeeze ; some fire in a fully automatic mode and others are limited to fixed bursts of two, three, or more rounds per squeeze.

Thus, modern automatic rifles overlap to an extent in design and function with machine guns.

In fact, many light machine guns ( such as the Russian RPK ) are adaptations of existing automatic rifle designs.

Generally, the difference between an automatic rifle and a machine gun comes down to weight and feed system ; rifles, with their relatively light components ( which overheat quickly ) and small magazines, are incapable of sustained automatic fire in the way that machine guns are.

Modern military rifles are fed by box magazines, while machine guns are generally ( but not always ) belt-fed.

While machine guns are often crewed by more than one soldier, the rifle is an individual weapon.