Definitions:

1. A firearm capable of fully automatic fire, meaning it can continuously fire rounds as long as the trigger is held down and ammunition is available. NOUN
   • The soldiers were equipped with machine rifles for the operation, allowing them to provide sustained firepower.
2. A lightweight, fully automatic firearm that uses small caliber rifle ammunition. ADJECTIVE
   • The light machine gun, a type of machine rifle, can be used for laying down suppressive fire in a combat situation.

Synonyms:

• automatic rifle
• light machine gun