We were once impressed by a triple-barrel revolver. Now it turns out Russia had secretly developed this four-barrel underwater gun over 30 years ago.
No one knew of its existence until the early '90s, when a Russian company put it into production for the public, so it's not surprising that James Bond never had to stare down its quadruple threat. The most unique aspect of the B-VI-307 -- besides having four smooth-bore barrels -- is that it doesn't fire traditional bullets. It's actually designed to be used underwater, where regular ammunition doesn't have much accuracy or range. So instead it fires 4.5-inch steel darts that can accurately travel 15-20 metres.