Also remember that a firearm is a specific type of weapon. I tend to call firearms weapons, but then again, I use the term weapon (or in real military speak, weapon-system) for any number of non-firearm weapons.
However, when dealing with people who are sensitive and gunshy, using language that minimizes use of a thing as a weapon can go a long way. It is just good practice to tailor your language towards your audience. For instance, do you talk the same way with your kids, friends, peers, superiors, or those you are in charge of? I know I don't (well, I don't have kids), and i tend to be polite to both those over, and under me, but that is because those under me actually know better than me, but I don't have to treat them with the same gloves as I do those with actual authority over me. (I can be more honest.)
For one couple I know whose kid killed himself with a pistol, I tailor what I bring up, and I certainly don't use the same hard-nosed language that I use amongst friends.