The Steyr IWS 2000 is an Austrian semi-automatic anti-matériel rifle, produced by Steyr Mannlicher. IWS stands for Infantry Weapon System. It is actually a smoothbore weapon, like many modern tank guns, and not a true rifle but this can help accelerate projectiles and increase ballistic effectiveness. It fires a 15.2x169mm armor piercing fin stabilized discarding sabot round (207 mm long), and is the first man-portable rifle to use this type of ammunition.
The first variant of the weapon was the AMR 5075. AMR stands for Anti-Materiel Rifle. It used a 14.5mm armor piercing fin stabilized discarding sabot round (200 mm long). The projectile was a solid tungsten fin-stabilized dart with a body diameter of 5.56mm.
Other variants are expected with the weapon still being under development.
This rifle is based on a nine-and-three-quarter inch long recoil mechanism. This mechanism, usually found in shotguns, helps manage the heavy recoil forces of the 15.2mm Steyr APFSDS round due to its damping effect that allows for force distribution over a longer period of time. Another unusual feature of this weapon is the movement of the barrel. After firing, the barrel recoils into a shock-absorbing hydro-pneumatic sleeve much like those found on a LG 1 Mark II 105 mm Howitzer. The IWS 2000 also uses a multi-baffle muzzle brake to distribute muzzle energy and further reduce recoil, similar to the ones used on D-30 2A18M 122 mm Towed Howitzers. The entire rifle body is made up of a combination of high-tension plastics and superlight polymers to increase manageability and cut down on weight. The smoothbore barrel is easily detached and packed away for increased mobility. The five-round box magazine is inserted on the right of the rifle at a 45-degree downward angle.
The projectile is a 15.2 mm fin-stabilized discarding-sabot type with armor-piercing capability. Specifically designed for the IWS 2000, it contains a rod-shaped penetrator of either tungsten carbide or depleted uranium, capable of piercing 40mm of rolled homogeneous armor at a range of 1,000 m, and causing secondary fragmentation. The cartridge comprises a plastic case, a steel head, and a plastic sabot shell around the penetrator.