A gun is a weapon because almost all of them are designed to kill, injure, or otherwise "Stop" something. My Glock 19 is a weapon because it's #1 purpose is to protect myself and my family. The Anshutz target rifle I used to shoot on the rifle team, conceivably might not be a weapon since it's primary purpose is to be used to punch holes in paper. Though I don't see many people calling it a hole punch.
I remember going through this when I used to play paintball in the mid-90's until early 2000's. They were trying to use the politically correct term paintball marker instead of paintball gun. The problem is, the only people who called it a marker were paintball players. People who didn't play, saw a gun that shot paintballs.
Us changing our lingo from weapon to pistol/rifle/revolver/shotgun/gun/whatever will do absolutely nothing to change the image of firearms. Those who are shooters know what these objects are. Those who are not see weapons. Back when people carried daggers and swords for self defense, were these not weapons? Technically, most firearms produced are primarily used as weapons. I understand that I shoot at targets far more than people with my Glock (never shot a person, don't want to shoot a person) but the primary reason I have it is to use it against someone who wishes me or my family harm. It is a weapon.
There's a time and a place for political correctness. This isn't one of those times or places. I call a spade a spade, and a weapon a weapon.