The SIG MKMS was sub-machine gun designed by Schweizerische Industrie Gesellschaft (SIG) company in Neuhausen during the early 1930s and was first introduced in 1933. It was designed for the military and to increase firepower it had a larger capacity magazine as well as a longer barrel, one that would be more common on an assault rifle. Only 1,228 of these guns were produced.
Read more about SIG MKMS: Design, Delayed Blowback Action, Other Features, Variants, Sighting Flaws