A shotgun slug
is a heavy lead
projectile, usually with pre-cut rifling
, often used for hunting large game. The first effective shotgun slug was introduced by Wilhelm Brenneke
, and his design remains in use today. Most shotgun slugs are designed to be fired through a smoothbore
barrel, which means that they must be self-stabilizing and capable of passing through a choked barrel
. Much later shotguns were produced with rifled
barrels, and slugs were designed to be fired from them with spin stabilisation. As these specialised "shotguns" were far more accurate than a smoothbore gun, they also usually featured greatly improved sights. Many of these slugs use saboted
sub-caliber projectiles, resulting in greatly improved external ballistics
Some less lethal shotgun ammunition is available in the form of slugs made of low-density material, such as rubber. See shotgun specialty ammunition for more information.
Shotgun slugs are used to provide rifle-like performance from a shotgun, by firing a single large projectile rather than a large number of smaller ones. In many populated areas, hunters are restricted to shotguns even for medium to large game, such as deer
, due to concerns about the extreme range of modern rifle
bullets. In these locations, a slug will provide more range and far greater killing power than a load of buckshot.
Rifled slugs are often used by police equipped with riot shotguns. Even out of a smoothbore barrel, the slugs will provide accuracy sufficient for antipersonnel use out to ranges about 100 yards (90 meters). This allows the officer the ability to use the shotgun as a reasonable substitute for a rifle at medium ranges.
The earliest shotgun slugs were just lead spheres, of just under the bore diameter, allowing them to pass through a choked barrel. Often called pumpkin balls
, these slugs showed very poor accuracy, and were only effective at the very close ranges where they could be relied on to hit the target in a vital area. Later types of slugs, the Brenneke and Foster slugs, used a weight-biased design and rifling
-like fins to provide stability and the ability to easily compress and pass through a choked barrel. These could be fired through a smoothbore barrel with reasonable accuracy, and significantly extended the effective range of the shotgun slug. The latest improvement is the saboted
slug, fired from a rifled shotgun barrel. The saboted slug and rifled barrel combination provides even greater accuracy than the rifled slugs, and the slugs themselves are more aerodynamic, providing more range and a flatter trajectory.
The Brenneke slug was developed by the famous German gun and ammunition designer Wilhelm Brenneke (1865–1951) in 1898. The original Brenneke slug is a solid lead slug with fins cast onto the outside, much like a rifled Foster slug. There is a plastic, felt or cellulose fiber wad attached to the base that remains attached after firing. This wad serves both as a gas seal and as a form of drag stabilization, much like the mass-forward design of the Foster slug. The "fins" impart little or no spin to the projectile; their purpose is to decrease the bearing surface of the slug to the barrel and therefore reduce friction and increase velocity.
Since the Brenneke slug is solid, rather than hollow like the Foster slug, the Brenneke will generally deform less on impact and provide deeper penetration (see terminal ballistics). The sharp shoulder and flat front of the Brenneke mean that its external ballistics restrict it to short range use, as it does not hold velocity well. The Brenneke slug in 12 gauge is well suited for large and dangerous game at close ranges, and deer sized game or antipersonnel use out to about 100 yards (90 meters). Brenneke slugs are somewhat more accurate than the Foster slugs, but are usually more expensive. With some new types of saboted Brenneke slugs, the range expands to 120-180 meters.
Brenneke slugs are loaded by a number of different makers (BRENNEKEUSA, FOB, ETC). Recently the Brenneke company, of Hanover, Germany, started marketing loaded ammunition, with Brenneke type slugs, saboted slugs, and buckshot.
A Foster slug
, invented by Karl Foster in 1931, is a type of shotgun slug
designed to be fired through a smoothbore shotgun
The defining characteristic of the Foster slug is the deep hollow in the rear, which places the center of mass very near the tip of the slug, much like a shuttlecock. If the slug begins to tumble in flight, drag will tend to push the slug back into straight flight. This gives the Foster slug stability and allows for accurate shooting out to ranges of about 75 yards (about 70 meters). Most Foster slugs also have "rifling", which consists of thin fins on the outside of the slug. Contrary to popular belief, these fins actually impart no spin onto the slug as it travels through the air. Since the slug is fired at a supersonic velocity, the nose of the slug pushing a shockwave creates a vacuum on the side of the slug, where the fins are located. The actual purpose of the fins is to allow the slug to safely be swaged down when fired through a choke, although accuracy will suffer when such a slug is fired through tighter chokes.
It is also possible to fire Foster slugs through rifled slug barrels, though lead fouling (build-up in the rifle grooves) can be a problem.
slugs are intended only for use in rifled barrels
or with rifled choke tubes, as they are not inherently stable. The slugs are generally significantly smaller than the bore diameter, increasing the ballistic coefficient
, and use the sabot to seal the bore and keep the slug centered in the bore. Saboted slugs, when fired out of a rifled barrel, can be far more accurate than slugs out of a smoothbore, and approach the accuracy of a typical hunting rifle.
Guns for use with slugs
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 does require some special considerations. 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
Many repeating shotguns have barrels that can easily be removed and replaced in under a minute with no tools, so many hunters will choose to purchase 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 rifled or smoothbore. Smoothbore slug barrels are quite a bit less expensive than rifled barrels, though they do limit the ammunition that can be used.
The recent improvements in slug performance have also led to some very specialized slug guns. The H&R Ultra Slug Hunter, for example, uses a heavy rifled barrel (see accurize) to obtain the most possible accuracy from slugs.
Shotgun slugs are banned in many countries in the world, due to their large diameter and lack of useful purposes for them, like most European countries, where big game hunting with shotguns is not allowed. Legislation differs with each country.
Shotgun slugs and buckshot are forbidden by law. Because the lack of any useful purposes in the Netherlands, the government sees no reason to change legislation. Large game (deer and wild boar) hunting is only allowed with large caliber rifles; shotguns are only allowed for small and medium- sized game, up to foxes and geese.
Rifled barrels for shotguns are an unusual legal issue in the United States of America
with rifled barrels are designed to fire single projectiles, and a firearm that is designed to fire a single projectile with a diameter greater than .50 caliber (0.5 inch, or 12.7 mm) is considered a destructive device
and as such is severely restricted. However, the ATF
has ruled that as long as the gun was designed to fire shot, and modified (by the user or the manufacturer) to fire single projectiles with the addition of a rifled barrel, then the firearm is still considered a shotgun and not a destructive device.
In some areas, rifles are prohibited for hunting animals such as deer. This is generally due to range concerns--shotgun slugs have a far shorter maximum range than most rifle cartridges, and are safer for use near populated areas. In other areas, there are special shotgun only seasons for deer. A modern slug shotgun, with rifled barrel and high performance saboted slugs, is the top choice for hunters who must hunt with a shotgun, as it provides rifle-like power and accuracy at ranges up to 125 yards (110 meters). This advantage also provides an interesting challenge for local governments who attempt to limit shooting in densely populated areas as the power and accuracy of shotguns with rifled barrels (or rifled slugs in smoothbore barrels) give slugs the power to cut through brush and tree limbs where smaller caliber rifle ammunition would typically ricochet or stop. Slugs for smoothbores, with their larger diameter and lower accuracy, are still suitable for wooded areas too. Their maximum effective range is about 75 yards (70 m).