The 6P29 and 6P30 (GRAU Indices), commonly known as the VSS "Thread Cutter" (Russian: ВСС «Винторе́з» Винто́вка Сна́йперская Специа́льная, romanized: Vintóvka Snáyperskaya Spetsiálnaya "Vintorez", lit. 'Special "Sniper" Rifle) and AS "Shaft" (Russian: АС «Вал»; Автома́т Специа́льный, romanized: Avtomát Spetsiálny "Val", lit. 'Special Automatic'), respectively, were a series of Soviet-designed rifles featuring an integral suppressor based on the prototype RG-036 completed in 1981 by TsNIITochMash. The two rifles hereafter are referred to as the Vintorez and Val. The Vintorez (beginning in 1983) and Val (beginning in 1985) were developed by TsNIITochMash to replace modified general-purpose firearms, such as the AKS-74UB, BS-1, APB, and PB, for clandestine operations, much like the PSS Vul. Manufacturing began at the Tula Arms Plant after its adoption by the Armed Forces of the Soviet Union in 1987. Design The Vintorez and Val are integrally suppressed and chambered in 9×39mm, a subsonic cartridge, in order to reduce its report. Four rows of nine holes are drilled in the barrel which follow the rifling and allows gas to escape the barrel behind the projectile into the expansion chamber which surrounds the barrel and extends ~20 cm forward of the end of the barrel where three baffles are located. The baffles are stamped out of a single sheet ~1 mm thickness and welded to a removable frame which is pressed against the front of the suppressor housing by a spring placed between the baffle assembly and the end of the barrel. The suppressor effectively reduces muzzle flash and muzzle report of the firearm to 130 dB. There are no design features which reduce the noise of the action. Manipulation is similar to many AK-type rifles: charging handle on the right side, tangent rear sight, magazine release button behind the magazine well, and safety lever above the trigger guard. The fire selector is, however, located behind the trigger within the trigger guard. The rifle also has an "AK-type" Warsaw Pact rail for various optical sights, namely the PSO-1-1, PSO-1M2-1, and 1-PN-51 calibrated for use with the 9x39mm cartridge. The standard open sights are graduated from 100 to 425 m in 25 m increments. The action is also similar to that of AK-type rifles with a similar long-stroke gas system with the piston located above the barrel. However, the design characteristically uses a rotating bolt with six locking lugs and a milled steel receiver. The Vintorez and Val share the same