Gevarm A6: An Open Bolt Semiauto .22 Sporting Rifle
13m
Gevarm, a gunmaking offshoot of the Gevelot cartridge company, produced a line of open-bolt semiautomatic rimfire sporting rifles from the early 1960s until 1995. This is an A6 model, the base type. It is chambered for .22LR, with an 8 round magazine and basic open sights. What makes these rifles unusual is the open bolt mechanism, which allows them to be extremely simple.
The bolt is a single part, with the firing "pin" in the form of a rib running all the way down the center of the bolt face. No extractor is built in, as chamber pressure alone is sufficient to extract cases in a simple blowback system like this one. Because it is an open-bolt firing design, one need not ever extract an unfired cartridge from the chamber.
Open bolt semiautomatic designs were prohibited in the US by ATF in the early 1980s, although existing guns in the country (like these) were grandfathered. They had never been popular sellers, though, because of their high price. The series produced included some with more sophisticated sights, one that simulated the look of an M1 carbine, some in .22 Short, and a takedown model.