Alright, while looking at a previous "limited ammo" idea, I came up with a version of my own, which is VERY customizable, alright, here it goes.
The host(Not any admin/super admin) can have a gui that allows him to put how much ammo he/she wants on each weapon, for example lets say I want 30 ammo I want a weapon to have, and I also would like it to have only 5 rounds, the player would then type in a number for how many rounds he wants and how many shots for each, here is my example of it(yes I know badly drawn)

So tell me what you think, also, it selects them from a list, so you don't have to manually add the weapons to the list, instead it has an arrow next to each one.