It's a Derringer, smithy. Small but effective. The last time I used it, fellow took two whole days to die. Bled to death inside. It was real, real painful.
9 seconds sound clip from the Back to the Future Part III movie soundboard.
You can hear this line at 00:57:39.381 in the DVD version of the movie.
Quote context
[...]
- What are you gonna do, boss?
- I figure if I bury this muzzle deep enough in his back, nobody will hear the shot.
- Careful, Buford. You ain't got but one bullet with that.
- I told you to watch your back, smithy.
- That means you'll be dead by about supper time Monday.
- Excuse me. I don't know who you think you are, but we're dancing.
- Well, look at what we have here. Ain't you gonna introduce me to the lady? I'd like a dance.
- I wouldn't give you the pleasure. You'll just have to go ahead and shoot.
- No, no. Emmett, I'll dance with him.
- Boys, keep the blacksmith company while I get acquainted with the filly!
[...]