Ground War

Ground War is a playlist for 12-18 players. It is the only playlist that can accommodate 18 players (except for Hardcore War in World at War), as all others are no more than 12 players. This gametype appears in Call of Duty 4: Modern Warfare, Call of Duty: World at War, and Call of Duty: Modern Warfare 2.

Tips (CoD4)
The pace of the game changes dramatically compared to regular modes. For example, camping becomes much harder as chances of being flanked increase.

The large amount of players and the general chaos makes team coordination difficult, especially for pick-up teams. While all weapons remain useful, perks can be even more important: explosive weapons such as RPGx2 and Fragx3 are lethal, and can be frowned upon in case of grenade spamming.

This mode is nonetheless great for achieving challenges revolving around explosive weapons or assists. Helicopters and especially bombing runs can inflict tremendous damage. Even allowing for the difficult "Carpet Bomb" challenge to be achieved.

Bandolier is a very useful perk, in particular for snipers, due to the large amount of enemies. As using the HUD map is even more important than in regular gameplay and UAVs are in almost constant use, the UAV jammer perk is very useful, and makes ninja SMG and sniper classes potentially devastating.

LMGs are also great, due to their ability to saturate an area with fire without having to reload.

Reloading after each kill is more dangerous than usual, as enemies will often arrive in quick succession, and players should either use sleight of hand, or resist the temptation to reload until more than half the magazine is empty or they are safely among friendlies.

Destroying the enemy choppers is very important in deathmatch modes, as they will often score multiple kills and bring the team ahead, 2 LMGs being very efficient at quickly bringing it down.

Call of Duty: 4 Rules
Maximum number of players: 18

Game modes: Team deathmatch and domination

Number of points to win: 1000 in Team Deathmatch, 200 in Domination

Points for a kill: 10 in Team Deathmatch, 5 in Domination

Points for an assist: 2 in Team Deathmatch, 1 in Domination

Points for capturing a flag (Domination): 15

Call of Duty: WaW Rules
Maximum number of players: 18

Game modes: Team deathmatch and War

Number of points to win: 10000 in Team Deathmatch, Capture all the flags in Domination

Points for an assist: depends upon amount of damage dealt

Points for a kill: 100 in Team Deathmatch, 5 in Domination

Points for capturing a flag (Domination): 30