Thompson Center Arms Contender

The customized firearm that Emiya Kiritsugu uses as a mystic code. It is a single-shot pistol originally developed for use in hunting and competitions. The barrel can be easily switched out, allowing it to be used with a large variety of bullet calibers. By fitting it with a handmade barrel forged using magical processes, and using special bullets that contain his own powdered ribs, Kiritsugu has transformed it into a deadly anti-magus weapon. Well, that's the short version; for a significantly more long winded explanation please refer to volume 2.
Incidentally, this gun was actually what made me want to write a story like Fate/Zero in the first place. In a way, you could say it was the start of everything. Or more specifically, it was Lance Henriksen's performance in Hard Target. I guess what I'm trying to say is, thank you so much, Mr. John Woo. Stranglehold was really fun. Will there be flying doves in Red Wall, too?

Fate/Zero material: Fate/Zero Encylopedia