Rat-shot cartridges are best used in dedicated smoothbore firearms such as Marlin Firearms' Garden Gun, but can still provide suitable patterns of shot from rifled barrels at short ranges. Since smoothbore firearms with barrels under a certain length may be classified as sawed off shotguns, rifled barrels are legally required in some cases. The Thompson Center Arms Contender pistols offered barrels in some calibers, such as .357 Magnum and .44 Magnum, in configurations that contained special straight rifled choke tubes to improve the patterns produced by the rifled barrels when shooting rat-shot cartridges.
Rat-shot is also used in some types of frangible ammunition, such as the Glaser Safety Slug. In these bullets, the shot is glued or sintered together inside a thin shell to form a projectile that fragments readily upon impact, reducing penetration and risk of ricochet.
While some makes of rimfire ratshot cartridges somewhat resemble traditional shotgun shells, with a brass case crimped closed, many other types of rimfire and nearly all centerfire rat-shot cartridges use a hollow plastic capsule, often shaped like a bullet to aid in feeding, which holds the shot. This plastic case shatters during firing, and allows the shot to disperse after it exits the muzzle.