Remembering that fetish means replacing normal object of sexual desire with the fetish object, I suggest you are seeing the gun as a phallic symbol.
A foot fetish.
An earlobe fetish.
Schediaphilia, is the word for that fetish. It is also know as toonophilia.
No one can say why for sure as with any other fetish, it's so weird it's called a fetish
Fetish for small spaces is called claustrophilia.
There isn't really a special name, probably because it is not very common. It is simply called an elbow fetish.
Watersports
That is too normal to be called a fetish. Most men are intensely aroused by the female buttocks and anus.
That's so obscure I don't think there's even a name for it. I think it would just be called a report card fetish.
There is a thing called a foot fetish,which is very common especially in male's. I don't have a foot fetish,and I know i'm not missing out on anything. A foot fetish is a sexual attraction to the feet. Usually the feet of a female. Girl's think of foot fetish boy's as "Creep's" or "Weirdo's" and I agree with them. Some has a fetish,and some have disgust. Which I have disgust.
When a male licks a woman's feet he likely has a foot fetish. The gender of the individuals is unimportant. When a man licks a woman's feet, it is often called a foot fetish. When a man licks a woman's feet, it is often called a foot fetish. When a man licks a woman's feet, it is often called a foot fetish.
The guns used in war to shoot down planes are called antiaircraft guns.