SIG's SG 551-SWAT is a gas-operated weapon conceived specifically for special forces and
elite units. Incorporating synthetics and corrosion-resistant materials, it is highly suitable for
maritime engagements. The weapon is based on the proven design concepts of the SG 551 (SG is an abbreviation for Sturmgewehr, or assault rifle) and is extremely compact. The optimal layout and outstanding weight distribution provide convincing accuracy and recoil characteristics.
The SG 551-SWAT is equipped with a highly tested and accurate sighting system. A combined diopter and snapsight shooting assembly is mounted on the receiver housing and calibrated for selected ranges. This rear sight resembles that found on HK rifles and submachineguns, and it is adjustable for both windage and elevation. It is also equipped with tritium-illuminated markings for night firing. The front sight is equipped with a protective hood and a flip-up night sight that is also illuminated with tritium. A universal scope mount is available for the SG 551-SWAT that accepts a wide range of sighting aids such as night-vision equipment, Trijicon ACOGs and other STANAG-based optics without the need for special tools or adapters. A universal fitting on the foresight mount accepts special equipment such as bipods or laser sighting aids and provides a safe means of attaching the weapon in transport vehicles.
SIG's engineers understand that specialists demand versatility and uncompromising quality in a weapon. With this in mind, all components of the SG 551-SWAT are manufactured to withstand the rigors of combat in any environment. Exposed steel parts such as the upper/lower receiver, sights, magazine release and trigger are coated in plastic to resist corrosion. The folding buttstock, pistol grip, handguards and magazine are all manufactured from high-impact synthetics. The gas system's components are made of stainless steel. The barrel, bolt, carrier, and firing pin are all made with steel that has been gas nitrided, hardened and tempered. The bolt and carrier, along with most other components internal to the receivers, undergo a special phosphating procedure. The result of SIG's engineering is a rifle that is especially suited for tropical and maritime operations.