I do not have time but I feel I can at least provide possible input
Design Concept for an Ammo Mod
Script_AmmoMod.whatever
Ammo and mags for each type of weapon is stored as a variable with that person. Ammo of a weapon type is refilled whenever a player picks up the weapon. Listens to the players for the fire method and decreases ammo on the gun they are holding. When ammo is depleted, a delay is applied to firing while that weapon is out until it replenishes from mag. Default mag limit is 3 or something and default ammo per mag is 9 or something. The server options then allow the admin to set for each weapon a ammo and mag limit manually. Possibly a save settings thing as well.
In case anyone wants to tackle this, however I am sure anyone who actually can would come up with a way to do this stuff already. I just felt this a good oppertunity to practice my "breaking down possible code needed for a project" thing I learned a while ago... I am tired, but I can kinda tell that everything above is stuff anyways. Whatever.