Shotgun slug
Slugs are designed for hunting large game, and other uses, particularly in areas near human population where their short range and slow speed helps increase safety margin.
The first effective modern shotgun slug was introduced by Wilhelm Brenneke in 1898, and his design remains in use today.
In the early development of firearms for the year 1875, smooth-bored barrels were not differentiated to fire either single or multiple projectiles.
As firearms became specialized and differentiated, shotguns were still able to fire round balls, though rifled muskets were far more accurate and effective.
Early slugs were heavier in front than in the rear, similar to a Minié ball, to provide aerodynamic stabilization.
Some of these slugs are saboted sub-caliber projectiles, resulting in greatly improved external ballistics performance.
In many populated areas, hunters are restricted to shotguns even for medium to large game, such as deer and elk, due to concerns about the range of modern rifle bullets.
In Alaska, seasoned professional guides and wild life officials use pump-action 12 gauge shotguns loaded with slugs for defense against both black and brown bears under 50 yd (46 m).
Examples include a less-lethal cartridge in the form of a bean bag round or other less lethal buckshot and slugs.
A traditional rifle would offer greater range and accuracy than slugs, but without the variety of ammunition choices and versatility.
Slugs are designed to pass safely through open chokes and should never be fired through tight or unknown barrels.
[4][5] A 1 oz (437.5 gr (28.35 g) 2.75 in (70 mm) Foster 12 gauge shotgun slug achieves a velocity of approximately 1,560 ft/s (480 m/s) with a muzzle energy of 2,363 ft⋅lbf (3,204 J).
A 180 gr (12 g) bullet at 2,775 ft/s (846 m/s), which is a very common 30-06 Springfield load and not its true maximum potential, achieves 3,079 ft⋅lbf (4,175 J) of energy.
Due to the slug's larger caliber and shape, it has greater air resistance and slows down much more quickly than a bullet.
The Taylor knock-out factor (TKOF) was developed as a measure of stopping power for hunting game, however it is a rather flawed calculation.
[7] It is defined as the product of bullet mass, velocity and diameter, using the imperial units grains (equal to 64.79891 mg), feet per second (equal to 0.3048 m/s) and inches (equal to 25.4 mm): Some TKOF example values for shotgun slugs are: To compare with rifles, some TKOF example values for rifle cartridges are: Full-bore slugs such as the Brenneke and Foster designs use a spin-stabilization method of stabilization through the use of angled fins on the slug’s outer walls.
Most saboted slugs are designed for rifled shotgun barrels and are stabilized through gyroscopic forces from their spin.
The soft metal, typically lead, fins squish or swage down in size to fit through the choke to allow for an easy passage.
Like the Brenneke, these ribs impart a rotation on the slug to correct for manufacturing irregularities, thus improving precision (i.e. group size).
Due to the fact that they do not contact the bore, they can be made from a variety of materials including lead, copper, brass, or steel.
Saboted slugs can vary in shape, but are typically bullet-shaped for increased ballistic coefficient and greater range.
The sabot is generally plastic and serves to seal the bore and keep the slug centered in the barrel while it rotates with the rifling.
In terms of safety, part of the shell may remain behind in the barrel, causing potential problems if not noticed and cleared before another shot is fired.
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 smooth bore, and pellets tend to form a ring-shaped pattern due to the pellets' tangential velocity moving them away from the bore line.
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.
Legal uses in the UK include, but are not restricted to, practical shotgun enthusiasts as members of clubs and at competitions, such as those run by or affiliated to the UKPSA.
Shotgun slugs have a far shorter maximum range than most rifle cartridges, and are safer for use near populated areas.
