Not to be confused with Dirty Magazines such as Playboy or Hustler.
A Dirty Mag relates to the use of a Bullet Type that considered "Bad" or "Not Ideal" for the situation its being used for.
Typically, this is used to describe a mixture of Hollow Point and Full Metal Jacket in a gun carried for self defense. Since Full Metal Jacket is NOT a safe self defense round due to its ability to overpenetrate. The magazine is a "Dirty Mag".
The name was derived from Dirty Magazines, how they were Taboo to have, and a Gun's "Magazine".
Instructor: Now boys, when you carry concealed you dont want FMJ in your magazind. It could overpenetrate your target and hit something or someone. You guys remember those playboy magazines?
Class: Yeah?
Instructor: Well, those are Dirty Mags. You're not supposed to have them because they're taboo. Putting an FMJ into your magazine makes it a Dirty Mag too, and if I catch you with one: Ill personally kick your ass. Understood?
Class: Yes Sir
The act of going to someone vendor in Fallout 76, seeing ridiculous prices, and nuking their camp.
"Yeah, they had ammo at 5 caps a piece, so I pulled a Dirty Mags and nuked that bitch."