Overloaded Backwash
From Halopedia, the Halo wiki
In backwash are glich very easy to do, first go to one of the bases and change your weapon for the sentinel beam, change the sentinel beam for the weapon again, wait a few secons and a other sentinel beam respawn with the previus beam in the map, repeat the proces any times and only if you move the sentinel beams with an explosion they will desapear.
