Actually in military use, 'gun' generally refers to larger crew-served weapons, like artillery. The word 'small arms' is used to describe rifles and hand guns.

Actually in military use, 'gun' generally refers to larger crew-served weapons, like artillery. The word 'small arms' is used to describe rifles and hand guns. 'Gun' can also refer to anything from a phaser to a portal gun to a zero point energy manipulation device!