Sabot - Design

Design

Since a strong seal is needed to trap propellant gases behind the projectile, and keep the projectile centered in the barrel, something is needed to fill the undesirable but necessary gap between projectile and barrel, a space referred to as the windage, and this is the role of the sabot. Firing a small size projectile wrapped in a sabot raises the muzzle velocity of the projectile. Made of some lightweight material (usually plastic in smallbore guns, and aluminium - and, in earlier times, wood or papier-mâché - in cannons), the sabot usually consists of several pieces held in place by the cartridge or a loose connection. When the projectile is fired, the sabot blocks the gas, and carries the projectile down the barrel. When the sabot reaches the end of the barrel, the shock of hitting still air pulls the parts of the sabot away from the projectile, allowing the projectile to continue in flight.

Sabots are used to fire the flechettes that form anti-armour kinetic energy penetrators. A sabot is also used to fire anti-personnel flechette rounds. This round consists of the outer cup (sabot) which holds numerous subcaliber darts. The sabot cup holds the individual flechettes together tightly until the sabot case separates after leaving the barrel. For reasons why a smaller diameter projectile can be desirable, see external ballistics and terminal ballistics.

Sabot-type shotgun slugs were marketed in the U.S. starting in about 1985. When used with a rifled slug barrel, they offer vastly improved accuracy compared to traditional shotgun slugs. They are now legal for hunting in most states.