Armour-piercing fin-stabilized discarding sabot

Armour-piercing fin-stabilized discarding sabot (APFSDS), long dart penetrator, or simply dart ammunition is a type of kinetic energy penetrator ammunition used to attack modern vehicle armour. As an armament for main battle tanks, it succeeds armour-piercing discarding sabot (APDS) ammunition, which is still used in small or medium caliber weapon systems.

Improvements in powerful automotive propulsion and suspension systems following World War II allowed modern main battle tanks to incorporate progressively thicker and heavier armor, while maintaining considerable maneuverability and speed on the battlefield. As a result, achieving deep armour penetration with gun-fired ammunition required even longer anti-armour projectiles fired at even higher muzzle velocity than could be achieved with stubbier APDS projectiles.