Whenever I had to register a handgun in the history of the old rules, the cop always told me, "Your weapon is on the desk," "Your card is with your weapon," i.e. they never seemed to call it a gun. It stuck and I've always called it a weapon. That's what it is anyway, as I see it, so I don't mind the term at all and use it myself quite a bit, though I don't have an aversion to the term gun or firearm, either.
I do HATE the term gat, or any of the others that seemed to come from the 'hood.
I have an original Gat, which is a pellet gun, and I've always wondered it that is where the term originated.