There are currently two basic types of shotgun slugs — rifled and sabot. There is some confusion that these are the same, but that’s not actually correct. However, both slugs share some similarities. The slug, which is basically the “bullet” for a shotgun, is essentially a solid, single-projectile that can strike a target with great force.
Unlike “shot,” it doesn’t contain the pellet “pattern” that can spread out and cover a large area. While shot can increase the chances of hitting a target — especially a moving one like a duck, pheasant, or even clay pigeon in flight — a slug delivers more force and is generally used for medium-sized game. That would include whitetail deer or similar-sized game.
However, understanding the principle of sabot requires understanding its history.
Meet the Sabot
Sabot — pronounced “Say-Bo” — was actually the name of a type of wooden shoe that was worn in some parts of Europe, notably France and the low countries. However, the term was also used for the strap across the instep of some shoes, notably sandal type footwear.
Somewhere along the way, the term was applied to a thrust-transmitting carrier that positions a missile in a gun barrel or other launching tube and in essence prevents the escape of gas ahead of the missile. The term likely entered the English lexicon in the mid-1800s with the invention of wooden devices that kept gun shells from shifting in the barrel and a comparison was made to the wooden shoes. Hence, few think of sabot and look their feet and instead think of how it applies to military weapons.
Sabot rounds have been increasingly used in large-caliber military weapons, such as tank cannons and large bore artillery in recent years. The sabot essentially allows for a narrower projectile with high sectional density to be fired through a barrel of much larger bore diameter with the maximal accelerative transfer of kinetic energy. This is accomplished after the sabot leaves the muzzle and separates from the projectile in flight. This essentially diverts only a very small portion of the overall kinetic energy.
The actual sabot component in projectile design is a relatively thin, tough, and deformable seal known as a driving band or obturation ring. It is used to trap propellant gases behind a projectile, but also keeps the projectile centered in the barrel, when the outer shell of the projectile is only slightly smaller in diameter than the caliber of the barrel. These driving bands and obturators — which are made from material that will deform as the projectile is forced from the chamber into the barrel — seal the full-bore projectiles in the barrel.
Moreover, some small caliber jacketed bullets do not normally employ driving bands or obturators because the jacket material may be deformable enough to serve that function, while the bullet is made slightly larger than the barrel for that purpose.
Development of Sabot Rounds
While the use of Sabot began some two centuries ago, the French military began to develop “saboted” ammunition in the 1930s, where a heavier sub-caliber core was surrounded by a lightweight sabot. The French military fielded two calibers (75 mm/57 mm for the Mle1897/33 75 mm anti-tank cannon, 37 mm/25 mm for several 37 mm gun types) in the early stages of the Second World War. Efforts to improve the design ended after France surrendered to Nazi Germany in June 1940.
Yet, in 1944, the British military further perfected the “discarding-sabot” projectiles, where a tungsten core was supported in a conventional gun by a light metal sabot that split and fell free after leaving the muzzle. That allowed the core to travel at an extremely high velocity, but it would lose its accuracy over long ranges — in excess of 1,000 yards — because of slight variations in the way that each Sabot detached from the Armour Piercing round about 100 yards after leaving the muzzle of the gun barrel.
The use of sabot artillery and tank rounds increased during the Cold War.
The U.S. Army has employed its M829 armor-piercing, fin-stabilized, discarding sabot (APFSDS) tank round with the M1 Abrams series of tanks to great success. The improved M829A1 even earned the nickname the “Silver Bullet” when it was used successfully during Operation Desert Storm in 1991 against Iraqi T-55 and T-72 tanks. According to the late Tom Clancy’s Armored Cav, one the kinetic energy of “Silver Bullet” successfully took out T-72s, while another M829 round managed to penetrate a sand berm and still successfully destroyed an Iraqi T-72.
The M829 has been further improved and consists of a depleted uranium armor-piercing fin-stabilized discarding sabot-tracer (APFSDS-T). It remains the primary anti-armor 120mm smoothbore round for the tank’s main M256 cannon. The kinetic energy projectile is capable of penetrating the frontal slope of all fielded armor systems and its high technology penetrator and sabot design provides a munition which is accurate at all combat ranges.
Sabot in Small Arms
Over the past century, there have been a few attempts to create small arms ammunition that utilize a sabot. These included flechette, and offered a few notable advantages including having very flat trajectory, which makes it is easier to hit a target at a distance, and retains energy better than a standard bullet thanks to a high sectional density. Flechette rounds also tend to have very low recoil thanks to their lower mass.
However, the disadvantages outweighed their advantages, and that included the fact the sabot leaves the muzzle at the same speed as the flechette. As a result, the sabot could fly somewhat randomly and thus present danger to by-standing soldiers, especially if it was ricocheting off the ground.
In addition, because of the small diameter and mass, flechettes would provide very low stopping and killing power compared to standard 5.56 mm bullets. That is because small sabot rounds lose energy due to air resistance much more quickly than large sabot rounds, and with low caliber sabots, the extra speed that is provided from a sabot is bled off very quickly by air resistance.
Yet, the same isn’t true with shotguns. In fact, a sabot can provide armor-piercing capability to a weapon that sorely lacks it. And at close range when used with a rifled barrel shotgun, can provide almost unexpected accuracy.
Shotgun Sabot — The Basics
Sabot slugs for shotguns work in a fashion similar to the aforementioned artillery rounds. Instead of loading the slug into the shell, this type of slug is usually encased in a wad or bore-sleeve that grips the rifling of the barrel, and that usually provides the projectile inside with the spin needed to fly smoothly. It is similar to the wad that surrounds birdshot.
Sabot slugs differ from traditional slugs, which are not designed to benefit from a rifled barrel, and due to the fact that the sabot slugs do not contact the bore, these can be made from a variety of materials including lead, copper, brass, or steel.
In essence, the small package of projectile and plastic cylinder is then loaded into the shell, and when fired, the plastic container spins inside the barrel; the barrel’s rifling imparts spin to the slug. Saboted slugs can also vary in shape but are typically bullet-shaped for increased ballistic coefficient and greater range.
The sabot is generally made with a plastic shell, which actually serves to seal the bore and keep the slug centered in the barrel while it rotates with the rifling. The sabot separates from the slug after it departs the muzzle. Saboted slugs fired from rifled bores are superior in accuracy over any smooth-bored slug options with accuracy approaching that of low-velocity rifle calibers. Instead of fitting a full slug into a shell, sabot slugs are encased in a plastic cylinder and then fitted inside the shell and can produce near rifle-like accuracy at close ranges.
In addition, when the slug is ejected from the barrel, the sleeve is released and the slug continues downrange, maintaining a spin as it travels, which enhances the accuracy of the projectile and increases the effective range — much in the way that a rifle bullet also provides greater accuracy.
In addition to greater accuracy, the other advantages include longer range and greater muzzle velocity.
BRI Sabot Enters the Market
While sabot rounds for artillery were developed centuries ago, sabot slugs for shotguns are a far newer innovation. The BRI sabot slug is generally considered to be the first slug to utilize a sabot and it was introduced on the market in 1968. It represented a significant departure from past slug design.
Originally known as the Kelly-McAlvin, and named after its inventors, the .50 Caliber 443 Grain Saboted Projectile was essentially little more than .50-caliber bullet loaded into a 12-gauge hull between two plastic sabots. Each sabot was there to perform the important function of protecting the slug from deformation in the bore, and further allowing the slug to retain its original shape for superior accuracy.
The rear of the slug was also hollow, originally filled with a piece of wooden dowel, which was present to help the round fly nose first from an unrifled barrel. The early BRI slugs were not especially accurate however, and it failed to gain much attention from sport shooters. As a result, sabot slugs were largely forgotten for years , and the Kelly-McAlvin design was little more than a footnote in the history of shotguns.
Improved BRI Sabot Slug
That changed when the BRI Sabot slug was reintroduced and quickly found use with police forces throughout the United States. However, in the late 1980s the rights to the design were purchased by Bob Sowash, who further redesigned it — and the result later became a popular option for big game hunting with rifle barreled shotguns in the early 1990s after Winchester and Federal each purchased the rights to produce the slugs.
It was the slug revolution that took place in the mid-1990s that saw mass interest in slugs, and in the industry sought to catch up with the accuracy that was provided by the TarHunt RSG-12 slug gun design, which was introduced in the market 1992. The RSG-12ga would later make it onto Field & Stream magazine’s 50 best guns ever designed, even when compared to the world’s best rifle designs.
The shotgun has been noted for remaining the “World’s Leader in Slug Gun Accuracy.”
Sabot Slug Features
One of the primary advantages of sabot slugs is the close-range accuracy, especially when the slugs are used with rifled shotgun barrels. Today’s modern 12 gauge slug in a sabot is basically comparable to a .72 caliber rifle bullet when fired from a rifled slug barrel.
That can provide considerable mass, yet, because of the weight the slugs don’t have tremendous range. Inside of 200 yards sabot slugs are extremely effective and accurate. In addition, many have hollow point designs perched in magnum shells, which can resulted in an astonishing wound channel when used against big game.
The sabot can also consistently group well out to 200 yards, which is considered necessary for hunting big game. At such ranges, the sabot slug has considerable accuracy when compared to a standard slug fired from a standard shotgun. Many slug shooters will argue that with right gun and slug combination, 200-yard shots are not out of the question — and even 250 yards is entirely possible.
In addition, unlike the spread of pellets common with birdshot, a sabot slug can provide a tremendous amount of stopping power on medium- to large-size game. Some 12 gauge sabot slug makers even claim that the slugs are able to generate in excess of 3,800 foot-pounds of energy at the muzzle — that puts the 12 gauge slug on part with the .338 Winchester Magnum in terms of pure muzzle energy.
The sabot slug isn’t one type of slug.
It is actually a variety of slugs that include plastic or paper sleeves, and could include various other materials and mixtures. Each of those will result in different performance and that will impact the accuracy and effective range. Prices can generally vary, but sabot slugs tend to cost a bit more than a box of rifled slugs.
While developed for use with law enforcement, the sabot slug in recent years has been used almost exclusively for hunting of game from deer to large game, and at ranges in excess of a rifled slug. Because of the stopping power, the sabot slugs have also found use as a home defense round, especially for those who have a lot of property and prefer the power of a slug over the spread of buck shot.
Addressing the Issues
A common misconception with sabot slugs is that they cannot or should not be used in a rifled shotgun barrel. In fact, a shot slug should always be used in a rifled shotgun barrel, as it helps provide the spin that provides the accuracy. The confusion may come from the fact that military sabot rounds are typically fired from smooth bore tank guns.
While a sabot slug can be fired from a smoothbore shotgun barrel, most hunters would see it as a waste as it would provide less than optimal performance — including reduced range and far less accuracy.
Sabot Vs. Rifled Slugs
Another common debate is whether sabot slugs offer a significant advantage over rifled slugs. Most hunters would also agree that this falls down to a matter of preference, and a lot would be largely dependent on the type of shotgun that is being used. It is possible to purchase a second shotgun or even to change barrels, but generally, most hunters would recommend that if you have a smoothbore shotgun to go with the rifled slugs, and if you own a rifled barrel shotgun, sabot would be the better choice.
That will no doubt confuse newbies — who should be forgiven for making the assumption that rifled slugs would work better in a rifled barrel. The truth is that a rifled slug in a rifled barrel offers no improvement, whereas the sabot slug used in a smoothbore would be less accurate but far more accurate in a rifled barrel.
The bigger issue for many is that sabot sleeves are slightly more expensive than rifled slugs, and that is owing to the more complex design. The sabot slugs with their complex sleeve feature more components and take additional steps to assemble. That in turn drives up the price. The other part of the equation is that the slug doesn’t actually come into contact with the barrel when it employs a sabot. That can mean it could be made of coppers and alloys, whereas rifled slugs are usually only made from cheaper and softer lead — which is being increasingly banned in some states and localities.
Another misconception is that sabot slugs will also provide greater velocity, but a lot is dependent on the type of primer, as well as the actual propellant and slug design, among several other factors. The fact that the slug is either rifled or sabot may actually have no difference on velocity. However, as sabot slugs are often loaded into premium rounds, they tend to be loaded at higher velocities. Some hunters find that sabot shells are faster, but this is not because of the slug itself.
Where sabot slugs have a clear advantage over rifled slugs is in terms of overall energy. This is not actually because sabot slugs have an inherent design that creates better energy, but because manufacturers often load them as premium rounds.
It is also important to note that rifled slugs and sabot slugs are two very different products, and when it comes to trajectory, sabot slugs have a clear advantage. That is simply because of the significant spin, which is actually caused by the rifled barrel, and not the slug itself. As a result, sabot slugs will have straighter trajectories in general compared to rifled slugs. But it is important to consider that shotguns are not typically used for long-distance shots, so the actual accuracy may only be noticed when the shooter needs to place a slug at the vitals of a deer or another game animal.
Essentially, comparing rifled slugs and sabot slugs is much a case of apples and oranges. For those who already own a shotgun, the choice may be largely dictated by the type of barrel in that firearm. For those starting from scratch, the issue is whether accuracy and range are an issue.
In some states, there is the issue of legality — a number of states have now prohibited the use of rifled barrels, which are essential for sabot slugs, for hunting. For years, New York State, for example, had a ban on shotguns with a rifled barrel.
The issue actually dates back to the National Firearms Act of 1934, which determined that firearms with rifled barrels that are designed to fire projectiles greater than .50 caliber (12.7mm) would be considered a destructive device and thus severely restricted. However, the Bureau of Alcohol, Tobacco, and Firearms (ATF) had 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 would still be considered a shotgun and not a destructive device.
Yet, in some areas, rifled shotguns are still prohibited for hunting animals such as deer. This is generally due to safety concerns, as shotgun slugs have a far shorter maximum range than most rifle cartridges. In other areas, there are now special shotgun-only seasons for deer. That often includes a modern slug shotgun, with a rifled barrel and high-performance sabot slugs, which can provide rifle-like power and accuracy at ranges over 150 yards (140 m). When in doubt, it is best to confirm what is allowed.
Today, the sabot slugs are generally a premium item and are produced by a number of manufacturers including Hornady, Lightfield Ammunition, Remington, Winchester and Federal.
With rounds costing upwards of $4 per shell, the sabot shells are on the expensive side — but hunters are paying for the accuracy and stopping power.