I think a lot of industries call their thing a gun actually. We use an android phone with a scanner at work for all sorts of things (product inventory, order management, assigning electronic tags, article lookups, etc) and most of us call it the gun. Its predecessor did look like a gun, so the origins of the name make sense, the name just stuck after we switched to a phone with a built-in scanner. We also have a date gun, which prints off best before date stickers.