The SK-46 was one of several post-WWII experimental self-loading rifle designs developed for testing by the Swiss military, or for commercial export. It was manufactured by SIG at Neuhausen in both 7.5mm Swiss and 8mm Mauser. The rifle is gas operated, with a rather complex tilting bolt action. It uses 5- or 6-round detachable box magazines much like the K-31 bolt action (the magazine capacity depended on caliber; 8mm was 5 rounds and 7.5mm was 6 rounds, to match the common clips/chargers used in each caliber).
One interesting element of the design was the use of a charging handle made to mimic the appearance and function of a traditional bolt action rifle. A similar approach can be seen on the German MP-35 submachine gun and G-41(M) rifle.
The SK-46 also incorporated a standard rail for attaching a 2.2x optical sight (not present on this rifle).