Team SWAT
From Halopedia, the Halo wiki
Team SWAT is a Halo 2 unranked Matchmaking gametype. Player had no shields, and spawned with a headshot weapon. Common startup weapons were the Battle Rifle, Covenant Carbine, or the M6C Magnum. Players do not spawn with grenades, and there are not normally weapons or grenades found on the map.
The lack of shields signifcanty increases the speed of the game. Headshots are usually crucial, as they can take down a person in one round or burst, compared to shooting the body where it can take upwards of two or three.