Many hunters hunt with shotgun slugs where rifle usage is not allowed, or as a way of saving the cost of a rifle by getting additional use out of their shotgun. A barrel for shooting slugs can require some special considerations. The biggest drawback of a rifled shotgun barrel is the inability to fire buckshot or birdshot accurately. While buckshot or birdshot will not rapidly damage the gun (it can wear the rifling of the barrel with long-term repeated use), the shot's spread increases nearly four-fold compared to a smoothbore, and pellets tend to form a ring-shaped pattern due to the pellets' tangential velocity moving them away from the bore line. In practical terms, the effective range of a rifled shotgun loaded with buckshot is limited to 10 yards or less.
[9] Iron sights or a low magnification
telescopic sight are needed for accuracy, rather than the bead sight used with shot, and an open choke is best. Since most current production shotguns come equipped with sighting ribs and interchangeable choke tubes, converting a standard shotgun to a slug gun can be as simple as attaching clamp-on sights to the rib and switching to a skeet or cylinder
choke tube. There are also rifled choke tubes of cylinder bore.
Many repeating shotguns have barrels that can easily be removed and replaced in under a minute with no tools, so many hunters simply use an additional barrel for shooting slugs. Slug barrels will generally be somewhat shorter, have rifle type sights or a base for a telescopic sight, and may be either rifled or smoothbore. Smoothbore shotgun barrels are quite a bit less expensive than rifled shotgun barrels, and Foster type slugs, as well as wad slugs, can work well up to 75 yards in a smoothbore barrel. For achieving accuracy at 100 yards and beyond, however, a dedicated rifled slug barrel usually provides significant advantages.
Another option is to use a rifled choke in a smoothbore barrel, at least for shotguns having a removable choke tube. Rifled chokes are considerably less expensive than a rifled shotgun barrel, and a smoothbore barrel paired with a rifled choke is often nearly as accurate as a rifled shotgun barrel dedicated for use with slugs. There are many options in selecting shotguns for use with slugs.
Improvements in slug performance have also led to some very specialized slug guns. The H&R Ultra Slug Hunter,
[10] for example, uses a heavy rifled barrel (see
Accurize) to obtain high accuracy from slugs.