Okay, how about this:-
This is a Blaster Pistol:-
This is a Blaster Rifle:-
This is a Heavy Blaster Rifle:-
So far so good.
But how about if this:-
is a Blaster Carbine.
Course, I say this purely because I have been buying a bunch of old WEG minis* recently, and most of the Rebel troopers available are armed with one of these, and it offends my sense of rightness that soldiers would go in to battle armed with pistols as their primary weapon. But the props are made from the same Sterling submachine guns as the Stormtrooper blasters above, and they are often weilded with two hands.
(Course, I'd have said a Blaster Carbine looks more like:-
and especially has a shoulder stock, and the gun the Stormtroopers have is a Blaster Carbine. but still.)
*Or, all to often, modern recasts