This is a five-round smooth bore revolver chambered for .410 shotgun rounds much like the modern Taurus Judge. It is the standard-issue sidearm for Norvelios physical security officers.
Instead of lead shot or slugs the specialty ammo used with this pistol is a crystalised anesthetic that is absorbed into the blood stream after penetrating the skin. The effect of this is numbness and loss of muscle function around the affected area followed by unconsciousness.
The barrel can change its interior diameter in the space before the muzzle to act as an adjustable choke. This can extend the effective range of the weapon and be adjusted quickly by the user by turning a collar on the barrel.