Utilizing a shotgun to defeat a door in CQB is a technique that is not only efficient but also relatively cost-effective in terms of specialized equipment. Really it requires very little other than a shotgun and the correct ammunition. The shotgun itself should be a tertiary weapon to the breacher’s sidearm and primary weapon in an ideal world. There are some determining factors to if a specific door may be breached using a factor though as well as added tools should alternative methods be required.
The biggest factors are the door’s shape, structure, and directional movement; these all equate to if a shotgun will be an adequate tool for a hard breach. Ideally all these aspects of the door and building should be determined prior to an assault or raid occurs but may need to be determined upon approach of the target building or point of entry. Situation dictates, so that kind of intel may not be available to everyone. For article’s sake, I will be describing the procedure from the perspective that breach information is acquired on approach to the breach-point. If the door is composed of a material that is destructible under a shotguns use, proceed. If the door is made of reinforced steel or something to that extent, an alternative breaching method should be used.
The shotgun itself should be set-up in a specific configuration to not only expedite the process but also ensure safe handling of the firearm during the breach and CQB process. The shotgun should be set-up in a modified Condition 3, that is a loaded tube and empty chamber; however, the safety should be left off to expedite the process. Rather than fumbling with the small safety (think the 870, although with other models I’m sure this could change), when the breacher reaches the door he simply has to chamber a cartridge and pull the trigger.