Follow up post on the SP4 ammo and in particular this weird revolver.

History

Designed in 2001 by Igor Yakovlevich Stechkin at TsKIB SOO an arms manufacturer based in Tula a city, 120 miles South of Moscow, famous for its arms manufacturing.

Purpose

The pistol was produced after a request from Russia’s security service, the FSB, for a quiet pistol capable of killing an enemy at 50 metres (55 yards).

Design

Like the Unica 6 this gun actually fires from the bottom chamber. This low bore axis design reduces muzzle climb when shooting, allowing faster follow up shots. The tube at the top is a laser sight, this is what that switch & wire on the left side connects to.

The grip is designed to balance the shooter’s desire to place their pinky finger on the gun with the need for the butt of the grip to be small, to aid in it’s ability as a concealed carry firearm.

The cylinder also swings out like a fence gate. I’m not sure if any other designs that do this, if you do please share them.

Also I believe that’s an ambidextrous safety, an odd feature on a revolver.

Source: https://www.historicalfirearms.info/post/74877616198/russias-silent-revolver-the-ots-38-the-ots-38