The VSS Vintorez is a specialized, sound-suppressed sniping weapon created in the late 1980s.
The VSS uses the 9X39mm round from the Soviet AS assault rifle, which the VSS itself is based on. The VSS is a selective fire weapon, although it is typically fired in semi-automatic mode when using the 10-round box magazine. It features an integral suppressor, which like the MP5SD2, does not need replacing, and operates on a similar principle as well.
Behind the scenes
The VSS appears in Metal Gear Solid 4: Guns of the Patriots, with its high penetrating power, combined with the integrated suppressor making it an effective weapon. It features the 3X and 10X zoom found on all sniper rifles in the game, and can only be procured in Act 2 in the left side of the Confinement Facility (where there is no battle). There are no modifications available for the VSS in the main game.
The VSS can take out a Gekko in less than 5 hits if aimed at the head in the right spot, thus making it better than the M14 for Gekko. In addition, this weapon is completely silent will allow it to kill Gekko easily and can be used without alerting other nearby sentries, when the M82 and Rail gun aren't an option (which both make a lot of noise).
While its effective range is comparable to the SMGs at only 150 meters, soldiers will almost never be that far away in the game. With its sniper scope, it is more than capable of killing even at the range limit. Due to the fact that its suppressor does not wear out, the VSS is very effective when going for even short range kills.