THIS IS UNCONFIRMED AND ISN'T NECESSARILY GOING TO BE ADDED
Try to attack. You'll see the ammo go down. Try to attack when your ammo is less than 1. You can't. Try to get your ammo past 3 without going into the project o_o. You can't get it past 3. Also I've done it in a way so you can change values of things without having to change the main bit of code.