When I was in the Army, we called M-16s weapons (I think weapon may have become the preferred term in the wake of Full Metal Jacket: "This is my weapon, this is my gun . . ."); gun referred to machine guns (or a mortar crew, i.e., 2 Gun); and I don't remember what we called pistols.

More seriously, I think perception counts a little. Not for the antis, but for the people in the middle who haven't made up their minds, or those who are not anti gun or hunting per se but might support some restrictive laws they believe are reasonable.