Hatton round

A breaching round or slug-shot is a shotgun shell specially made for door breaching. It is typically fired at a range of 6 inches (15 cm) or less, aimed at the hinges or the area between the doorknob and lock and doorjamb, and is designed to destroy the object it hits and then disperse into a relatively harmless powder.

Breaching rounds are designed to destroy door deadbolts, locks, and hinges without risking lives by ricocheting or by flying on at lethal speed through the door, as traditional buckshot can. These frangible rounds are made of a dense sintered material, often metal powder in a binder such as wax, which can destroy a lock or hinge and then immediately disperse. They are used by military and SWAT teams to quickly force entry into a locked room. Amongst police, these rounds are nicknamed "master keys", and their use is known as "Avon calling". Ideally, breaching rounds may be used in a standard combat shotgun or riot shotgun, or in a specialized shotgun, often attached to a rifle, such as the KAC Masterkey or M26 Modular Accessory Shotgun System. The most effective use of this round is with a "stand-off breacher" attached to the muzzle of a specially converted shotgun. The stand-off is held on the surface of the door and vents gases to prevent overpressure.

Though designed not to endanger people behind or around a door, a breaching round is easily lethal if fired directly at a human target.

Examples of breaching rounds are:

...
Wikipedia