For those interested in tinkering with limited ammo and jamming rules, I highly suggest checking out the old TSR game 'Dawn Patrol'. After playing many similair games (Richthofen's War, Wings, Blue Max etc) I have found this system to work very well.
In a nutshell, each gun starts w/ a set amount of ammo that is indicated in 'points' (50 for Spandau, 40 for Vickers, 10 per Lewis drum) Each time you fire a burst, you decide if you want to fire short (-2 points for each gun), intermediate (-3 points), or long (-4 points).
For jamming, the first time you fire you roll dice, and have a 5% chance to jam on a short or int burst, and 10% on long. each successive time you fire that chance stays at 5% if you fire short, or goes up 5% for int and long bursts. each time you do not fire in a turn, it goes down 5%.
If you do jam, you then must roll to UNjam (35% for short, 25% int & 15% long)
I find this to be a nicely balanced model that is somewhat realistic, and easily can be adapted without losing much of the 'fun' out of the game. For more on Dawn Patrol & those actively playing check out-
dawnpatrol.org - Home
We have incorportated the WoW miniatures into the game, which has created newfound interest!