Chinese underwater guns
The recently aired CCTV documentary has confirmed that the secretive Chinese underwater guns are based on the Russian designs*

The Russian SPP-1 4.5mm underwater pistol can accommodate either a twin or quad-barrel arrangement with a cartridge in each which is inserted into the pistol's breech. The Chinese QSS-05 5.8mm adoption (or 山寨) has a tri-barrel pistol arrangement.

The Chinese also "山寨-ed" the Russian APS Underwater Assault Rifle to fire the Chinese 5.8mm rifle round.
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