Door breaching

Door breaching is a process used by military, police, or emergency services to force open a closed and/or locked door. A wide range of methods are available, one or more of which may be used in any given situation. These methods may be divided up into mechanical breaching, ballistic breaching, and explosive breaching.

Mechanical breaching
Mechanical breaching can be minimally destructive, through the use of lock picks. This method is relatively slow and requires a trained operator, but does not damage the lock or door.

More dynamic methods use force to break the lock or door. The common methods are to use a lever, such as a Halligan bar or crowbar, or to use a tool to concentrate a large amount of force on the door, such as a sledgehammer, hydraulic jack, or battering ram.

Ballistic breaching
Ballistic breaching uses a projectile weapon to breach an opening. Weapons used can range from the 120mm cannon of a main battle tank with a HEAT round, which will breach most obstacles easily, though the force involved may be far beyond the rules of engagement. A less damaging ballistic breach needs to destroy either the latch and lock, or the hinges of the door, and the ideal choice for this is the shotgun. While in theory other firearms can be used, handguns are underpowered and rifles are less effective than the shotgun and pose a far higher risk of ricochet and collateral injury. Most shotgun ammunition can be used for breaching, though the risk of injury varies with type. Of the available shotgun ammunition, shotgun slugs pose the highest risk, as they will retain significant energy to cause lethal wounds well after they have penetrated the door. Buckshot is far safer, and birdshot even safer, as the multiple small projectiles disperse quickly after penetration, reducing the chances of causing a lethal wound. The safest option is a frangible round such as the Hatton round, which turns to dust upon penetrating the door, and disperses completely upon exit.

Breaching a door with the fewest number of shots possible is both faster and reduces the chance of collateral damage. Attacking the latch and lock is easiest, as it requires fewer shots and is easiest to target, whereas attacking the hinges requires more shots, and the hinges may be hidden from the outside. Careful aim is required; shots to the lock side are fired at a point halfway between the lock or handle and the door frame in order to hit the bolt holding the door shut. According to US urban warfare doctrine, the breaching operation is performed with the muzzle in contact with the door, or as close as possible, and angled downwards at a 45 degree angle. This process provides the best chance of hitting the desired point, while minimizing risk to occupants of the room being breached. Muzzle attachments are available on some specialized breaching shotguns to facilitate this operation, by holding the barrel securely in place while providing a slight standoff to allow powder gases to escape.

Magazine capacity and operating mechanism are also important consideration in a breaching shotgun, because to quickly breach a door requires the ability to quickly fire multiple shots. For a breach on the latch side, US doctrine calls for two shots to be fired, and then an attempt made to open the door. If the door cannot be open, the process would need to be quickly repeated. If the hinges must be breached, then doctrine calls for three shots per hinge followed by an attempt to open the door.

Explosive breaching
Explosive breaching can be the fastest method, though it is also the most dangerous, to both the breachers and the room occupants. Depending on the situation, explosive breaching is potentially slower than a ballistic breach due to the large standoff required when using explosives, if there is no cover available. Breaching can be performed with a specially formed breaching charge placed in contact with the door, or with various standoff breaching devices, such as specialized rifle grenades like the SIMON breach grenade.

Breaching using explosives is primarily an operation performed by highly trained explosives experts, such as combat engineers. Explosive breaching charges can range from highly focused methods, such as detcord, plastic explosives, or strip shaped charges that explosively cut through doors or latches, to large satchel charges, containing 20 pounds (9 kg) of  C-4, that can breach even reinforced concrete bunkers.

Explosive breaching is described in verse 9 of this poem by Rudyard Kipling.