Tracking Ammo

I've been throwing ideas around for a zombie game for ages, ever since I heard of All Flesh Must Be Eaten but was too cheap to buy it.

I circle around hacking games that I already know about - Risus, In A Wicked Age, Apocalypse World - and would want to use Liverpool as a setting because (a) that's where I live, and (b) I think it would be neat to have big city centre maps that get updated over time to show what has happened where - where there are road blocks, where other survivors might be etc. I'm still testing ideas out on paper with different systems, and aim to share these as time goes on.

Anyway, that's all preamble. The thing that I want to share is an ammo tracking mechanism. I thought it might be a nice halfway house between the "infinite ammo until you really fail a roll" that I have experienced in Apocalypse World and the "track every single bullet you fire" of Cyberpunk.

(not that there is anything wrong with either of these, of course)

Ammo is by default very rare. A gun has a rating from 0 to 6. After each time a character fires their gun (by whatever in-game mechanism that has) they roll a d6:

• If they roll higher than or equal to their current rating, they reduce their rating by 1.
• If they roll less than their current rating they stay on that rating.

So, if a person starts with a 6 their clip/magazine etc is effectively full. As time goes on, after every roll they make, the chances are that they are going to have less and less ammo in their gun. When the rating gets down to 1 they know that the very next time they shoot the gun it will be out of ammo.

I think that this mirrors the way that hit points and damage were presented to me in the past: when you have only lost one hit point, that's like a scratch or a graze; when you're down to less than a quarter you could be in serious trouble. In the same way with ammo, on a 4 you have let some shots off but you're alright; if you're in a pitched battle and your shotgun has a 2 rating you had best find a way out of the danger zone.

Anyway, I'm sharing this for a reason: what do you think? Any thoughts? Any tweaks?