Automatic pistol and Automatic firearm

Automatic pistol noun - A pistol that will keep firing until the ammunition is gone or the trigger is released.

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

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

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