Automatic rifle and Automatic firearm

Automatic rifle noun - Light machine gun.

Automatic firearm and automatic rifle are semantically related. In some cases you can use "Automatic firearm" instead a noun phrase "Automatic rifle".

Automatic firearm noun - A firearm that reloads itself and keeps firing until the trigger is released.

Automatic rifle and automatic firearm are semantically related. Sometimes you can replace phrase "Automatic rifle" with "Automatic firearm", this phrases are similar.