The Swiss concern of Schweizerische Industrie-Gesellschaft (SIG) was responsible for several post-World War 2 self-loading rifle, selective fire projects and among these was the "AK-53" of 1953. This long gun was designed as a "battle rifle" chambered for the local 7.5x55mm Swiss cartridge. It was rather unique in its use of a blow-forward operating system and this wass used to feed cartridges from a 20-round detachable box magazine. However, the AK-53 only existed as an experimental rifle and about 50 or so of the type were completed before the end.
Despite the use of "AK" in the designation, the AK-53 had no relation to the classic line of Kalashnikov assault weapons of Soviet origin.
Very few firearms have relied on the blow-forward method of operation - the first being the Austro-Hungarian Mannlicher Model 1894 service pistol. The process involves the bullet "pulling" the barrel forward (in the case of the AK-53, by way of a piston) as it moves down the bore (the bolt remains in place). This action is used to eject a spent cartridge casing from the chamber and bring a fresh cartridge in line for the next shot. One of the chief benefits of the blow-forward system is in allowing a rifle to be of shorter overall length but, as with any advantages, there also are disadvantages (detailed below).
The AK-53 used this system tied to a gas-operation. The product's aim was to devise a select-fire rifle suitable for mass-production but buyers appeared few and far between. The design sported several deficiencies as the blow-forward system increased jamming and reduced accuracy (no thanks to the moving barrel assembly) while rate-of-fire was inherently low. The heat built up through the closed breech arrangement also held the potential to prematurely ignite (cook off) an awaiting cartridge while it lay in the chamber.
All this coupled with the post-World War 2 gun market being saturated with surplus goods and the AK-53 was forced to the back pages of history in short order.
Outwardly the gun carried a highly conventional look about it. A single-piece wooden stock was in play that made up the forend, receiver, and butt. A useful pistol grip was installed aft of the trigger unit and the magazine well was ahead of the trigger. The metal components were inlaid and the barrel section protruded well-ahead of the forend. Curved magazines were used.