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.
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.
The fetish of consuming urine is known as urophagia. It falls under the category of urolagnia, which refers to sexual pleasure gained from urine in general.
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.