I was wondering about this.

Possible stats:

Luck-Affects the chance of the bullet being loaded or rolled to shoot you. This isn't a gamebreaker, though.
Premonition-Affects the visual cues on the screen, though once again, not a gamebreaker.
Deception
"Poker face"
Sleight of hand
Observance

I imagine there might be different types of pistols.

Oh, and it isn't entirely random. Which bullet is loaded is affected by whenever it is rolled and when the game starts.

Oh, and you can also shoot an opponent, although I imagine there might be a skill to give you the slight chance of "redirecting" a shot to someone else in the game.

No hp or anything like that.

It sounds a bit ridiculous, but I'll bite (assuming it's a small minigame in a bigger game). The direction you're going sounds a bit like the card game Cheat/Bullshit, e.g. either party can cheat with the gun, either party can call them out on it, but calling falsely leads to death. Observation could also apply with regards to spinning, e.g. you may be able to hear the bias the weight of the bullet imparts on the spin. Or you may be able to tell if the other guy loaded more or less bullets than expected. I think also guts/fearlessness would be a potential factor, e.g. fear might reduce your observation, ability to do sleight of hand, or ability to pull the trigger. If you think you'll actually be shot you could shoot the other guy, but if there's no bullet then you lose due to bad faith/his guys shooting you. ;)

It sounds a bit ridiculous, but I'll bite (assuming it's a small minigame in a bigger game). The direction you're going sounds a bit like the card game Cheat/Bullshit, e.g. either party can cheat with the gun, either party can call them out on it, but calling falsely leads to death. Observation could also apply with regards to spinning, e.g. you may be able to hear the bias the weight of the bullet imparts on the spin. Or you may be able to tell if the other guy loaded more or less bullets than expected. I think also guts/fearlessness would be a potential factor, e.g. fear might reduce your observation, ability to do sleight of hand, or ability to pull the trigger. If you think you'll actually be shot you could shoot the other guy, but if there's no bullet then you lose due to bad faith/his guys shooting you. ;)

Actually, I was thinking of something more like http://www.newgrounds.com/portal/view/596354, although those elements could still fit in. I want to keep the tone and mood, where every shot could be your last, and you had to wonder whether or not it would be worth spinning the wheel or shooting the opponent.