http://www.patreon.com/ForgottenWeapons

The N33 is one of a series of Swiss prototype semiautomatic rifles developed between WWI and WWII (the "33" refers to 1933). This particular design is interesting because it fires from an open bolt, a feature generally seen on light machine guns. An open bolt rifle typically is more difficult to shoot accurately because of the time between trigger pull and firing as the bolt travels forward to load a cartridge before firing it.

The N33 was made in several calibers, but never went into any sort of significant production.