In Call of Duty 4: Modern Warfare, a breaching charge is seen in multiple campaign missions, though it is not usable by the player. It is used by Lieutenant Vasquez in "Charlie Don't Surf", and Gaz in "Ultimatum". It is a small explosive attached to the handle of a door to blow the lock. The explosive used in-game consists of a fuse igniter (specifically a M60 Time-Blasting Fuse Igniter), a slightly coiled length of cord which is most likely to be Detonating Cord, and a blasting cap at the end of the cord. The breaching charge does not damage the player even if he stands next to it, compared to scripted C4 everywhere except for in "Mile High Club".
In Call of Duty: Modern Warfare 2, the breaching charge is used much more extensively. In this game it is a "frame charge" — a shaped directional charge taped to a piece of Styrofoam, which is stuck to a door or wall to blast through the entrance.
It is seen in multiple Campaign and Special Ops missions. For a short time following the breach, events will occur in slow motion, allowing players to clear a room before any hostiles can effectively react, as they will be drawing and firing weapons at a much slower pace than normal. In addition, the player's magazine will be loaded to full capacity, no matter how many rounds were present previously.
In order to breach, the player must have a firearm equipped, and the room the player currently occupies must be free of enemies. If player attempts to use an invalid weapon, such as an RPG-7 or a Riot Shield, or is in the middle of a reload or weapon switch, a message will appear stating "Not ready to breach". A similar message will appear if there are still hostiles on the player's side of the door to be breached.
Frame charge in Modern Warfare 2
Breaching charges seen in Call of Duty 4 are found on the kitchen table in Loose Ends in Modern Warfare 2.
In Call of Duty: Modern Warfare 3, different types of breaching charges are seen depending on the type of material that needs to be breached. For example, the variant seen in Call of Duty: Modern Warfare 2 is used to breach simple wooden doors, while larger charges with multiple components are used to breach heavy submarine doors.
In Modern Warfare 3: Defiance, breaching is different to the other games that feature the breaching charge. The breaching charge in Defiance has a different appearance from others. Breaching can kill the player if they stand in front of the door while the charge explodes and the player is always told to plant the charge on doors. No action is seen when planting the charge and the breaching charge always appears instantly. There is a small slow-motion sequence after the breaching charge explodes, slowing down everything in gameplay. The slow-motion effect wears off after a few seconds but happens quickly. Friendly NPCs will usually shout "Go! Go! Go!" slowly just as the slow-motion sequence starts. There is only one time that the slow-motion sequence won't take place and is in the mission Through the Mountains.
A unique breaching charge is used in the level "Atlas Falls", known as Ice Charges. It is used later on in the same level to breach a door. A variant is also used in the level "LOKI", where it is used to get inside of the LOKI Space Station.
Breaching charges can also be used in Multplayer on the maps Octane and Warhawk. Walls marked with a red Ghosts symbol can be permanently blown up to open new lines of sight, destroy cover, or access new paths through the map. Players just walk up to the symbol, press and hold "Use" for 1 second, and a 3-second C4 charge will be placed on it. Players best stay clear of the charge or else suffer damage, possibly death, from the breach's explosion.