In the United Kingdom, however, shotguns must have a minimum barrel length of 24" to be eligible for ownership on a Shotgun Certificate, and shotguns with barrels under this length (which includes Coach guns) must be obtained on the more stringent Firearms Certificate. Some modern coach guns feature internal hammers as opposed to the traditional external hammers.
In the United Kingdom, shotguns need at least a 24-inch barrel to be registered on a Shotgun Certificate, whereas those with shorter barrels (like coach guns) must obtain them via a more rigorous Firearms Certificate. Some contemporary coach guns incorporate internal hammers rather than traditional external hammers.