From Norwegian patent 8564, April 11 1899.

Other Pictures:
Landstad automatic revolver

Landstad cylinder mid-rotation. Note how it is flat, with only two chambers.

Left side, disassembled

Right side, disassembled

The Landstad revolver
was an automatic revolver of Norwegian origin. The weapon had an unusual feeding device that used both a 2 round cylinder and a grip inserted magazine.

It was chambered for the 7.5mm Nagant cartridge, which at the time of the creation of the Landstad was also used in the Swedish Mod. 1887 and Norwegian Mod. 1893 Nagant revolvers.

History
The revolver design was patented in 1899 by Halvard Landstad, from Kristiana (now known as Oslo). Landstad designed the revolver with his own money and presented it to military trials in 1901. The gun never went into production because the revolver failed in the trials, but the inventor kept a prototype of the gun. It was donated to the British NRA after the inventor`s death in 1955. In 1977 the revolver was sold in an auction.

Weapontype:
Automatic revolver

Manufacturer:
Halvard Landstad (prototype)

Operation:
blowback

Cartridge:
7.5mm 1882 Ordnance

Magazine Capacity:
6 rounds

Feed system:
2 round cylinder and a grip inserted magazine.