DSR - Precision GmbH DSR - 1 The DSR - 1 is a compact bolt - action rifle designed , manufactured and marketed by the German company DSR - Precision GmbH and was ( until 2004 ) marketed also by the German company AMP Technical Services as a specialized sniper rifle for police sharpshooters . It has been adopted by the German GSG 9 counter - terrorist unit , as well as by other European special police units and agencies . Design details . The DSR - 1 system is configured in a bull - pup design , with a free - floating barrel . The folding bipod is mounted onto upper rails ( above the barrel ) , and the adjustable horizontal front grip is mounted on the lower rails ( under the barrel ) . The rifle features a fully adjustable rear stock and cheek piece . The holder for a spare magazine is installed in the front of the trigger guard to decrease reloading time . The DSR - 1 action features a benchrest match - grade , fluted barrel that is quickly interchangeable and is fixed into the receiver by three screws . The bolt features six lugs that lock directly into the barrel . The barrel is protected by a ventilated aluminium handguard and is fitted with a muzzle brake ( which is very useful when firing full - power , magnum loads ) . The trigger is two - stage and adjustable . The DSR - 1 features a manual , ambidextrous three - position safety , located above the trigger guard . For the standard version of the DSR - 1 a tactical suppressor is available . The suppressor is designed to be used with high power ammunition of the DSR - 1 chamberings . This suppressor effectively suppresses the muzzle blast . Naturally it cannot suppress the crack of a supersonic projectile but the direction where the bullet comes from is effectively concealed . The tactical suppressor is easily mounted in seconds on the muzzle brake using a quick release lever . The expected accuracy of the DSR - 1 is high : some sources state sub 0 . 2 MOA accuracy ( 0 . 20 inch / 5 mm groups measured center - to - center at 100 yards / 91 , 4 meters ) with match - grade ammunition and favourable environmental conditions . In an article on the DSR - 1 rifle the German gun magazine Visier performed test shoots with a DSR - 1 to get an indication of its accuracy potential with factory ammunition in October 2003 . The 5 - shot groups were obtained by test shooters whilst shooting from the bipod and measured from centre to centre . The table shows that with target factory ammunition the DSR - 1 performs in the 0 . 34 - 0 . 63 MOA region . If the DSR - 1 can perform better under ideal environmental conditions with to the particular rifle tailored handloads and / or if the human test shooters are a limiting factor was not tested by Visier magazine . An article on the DSR - 1 in the French Armes & Tir November 2001 gun magazine corroborates the German Visier results . The Armes & Tir test shooters used RUAG target cartridges and could shoot 200 x 300 mm ( 0 . 69 x 1 . 03 MOA ) groups at 1 , 000 m distance with a . 338 Lapua Magnum chambered DSR - 1 rifle . Variants . The DSR - 1 Subsonic is a DSR - 1 variant . The DSR - 1 Subsonic is optimized for 7 . 62x51mm NATO / . 308 Winchester subsonic ammunition usage . The barrel length is reduced to 310 mm . The 8 inch twist rate of the barrel is especially adapted to stabilize the long heavy projectiles used in subsonic ammunition . The propellant charge of subsonic ammunition is reduced to keep the bullet velocity ( 300 m / s - 320 m / s ) below the speed of sound ( ~ 340 m / s ) . At this subsonic speed the supersonic crack that arises when standard ammunition is fired is avoided . The manufacturer recommends exclusive use of subsonic ammunition for the DSR - 1 Subsonic . The DSR - 50 Sniper Rifle is an enlarged variant of the DSR - 1 . It has an integrated hydraulic recoil damping system in the buttstock and an integral muzzle brake . The forward - venting muzzle brake , also described as a linear compensator reduces the perceived muzzle blast . The DSR - 50 Sniper Rifle is chambered for the . 50 BMG ( 12 . 7x99mm NATO ) cartridge that is significantly larger than the . 338 Lapua Magnum cartridge , which is the biggest available chambering for the DSR - 1 rifle . Sniper rifles chambered in . 50 BMG are often employed as anti - materiel rifle s .