Use a text editor, such as Notepad, to edit the "WarInput.ini" file found in either of the following folders:

In Windows XP: "\Documents and Settings\\My Documents\My Games\Gears of War\"
In Windows Vista: "\\Documents\My Games\Gears of War for Windows\Wargame\Config\"

Add or change the following lines in the file.

[Engine.Console]
ConsoleKey=Tilde
TypeKey=Tilde
MaxScrollbackSize=1024
HistoryBot=-1
bEnableUI=True

Start the game and press ~ to display the console window. Then, enter one of the following codes to activate the corresponding cheat function. Note: Enabling a code will prevent achievements from becoming unlocked.

Effect	Code
Set number of grenades set	WarfareGame.Weap_Grenade magsize [number]
Set Lancer clip size set	WarfareGame.Weap_AssaultRifle magsize [number]
Set Magnum handgun clip size set	warfaregame.weap_locustpistol magsize [number]
Set semi-automatic clip size set	warfaregame.weap_locustassaultrifle magsize [number]
Set shotgun clip size set	warfaregame.weap_shotgun magsize [number]
Set sniper rifle clip size set	WarfareGame.Weap_SniperRifle magsize [number]
Set handgun clip size set	warfaregame.weap_cogpistol magsize [number]
Set Torque Bow clip size set	WarfareGameContentWeapons.Weap_Bow magsize [number]
Set Baird's default health set	WarfareGameContent.Pawn_COGBaird DefaultHealth [number]
Set Carmine's default health set	WarfareGameContent.Pawn_COGCarmine DefaultHealth [number]
Set Cole's default health set	WarfareGameContent.Pawn_COGGus DefaultHealth [number]
Set Dom's default health set	WarfareGame.Pawn_COGDom DefaultHealth [number]
Set Marcus' default health set	WarfareGame.Pawn_COGMarcus DefaultHealth [number]
Set Minh's default health set	WarfareGameContent.Pawn_COGMinh DefaultHealth [number]

Note: This procedure involves editing a game file; create a backup copy of the file before proceeding.