Unlimited ammo

Getting Unlimited Ammunition for a weapon is one of the easier and more common goals for some players.

One way is to give an ally a weapon. Even if there is one round left when you give them it, it will never deplete unless you use it again, but you still need to reload. Another is to play co-op, and continue kill your partner in a safe zone to get a huge amount of dropped weapon. Use this in campaign.

Another way you can get unlimited ammo you can only do in Halo 3 multiplayer. You can edit a level in custom games by pressing the small x button on the controller on the main custom games screen. Then, you can set all weapons on the map to have unlimited ammo.