The Steyr IWS 2000 is an Austrian single-shot bolt-action anti-materiel rifle produced by Steyr Mannlicher. IWS stands for Infantry Weapon System. Unlike other anti-tank rifle designs, it has a smoothbore barrel. This facilitates higher projectile velocities and allows a longer barrel service life, but the lack of gyroscopic spin-stabilization requires the projectile to have aerodynamic stabilizing fins instead. The IWS is chambered in a 15.2×169 mm armor-piercing fin-stabilized discarding-sabot cartridge, and is the first man-portable rifle to use this type of ammunition.