The Danuvia submachine gun (better known as "Kiraly submachine gun") was developed in the late 1930s by the Hungarian weapons designer Pál Király. Outwardly and constructively, it resembles the earlier Swiss SIG MKMS, which was developed by Király (who worked at SIG until 1937); accordingly, it uses a similar lever-delayed blowback mechanism, unusual for a submachine gun of this era. The first exemplars were made in November 1938. It was adopted by the Hungarian army in 1939 under the designation 39.M and was produced at the Danuvia Gepgyar plant, but mass production did not start until the beginning of 1942. In 1943, a more compact model 43.M was developed, which had a folding buttstock and a shortened barrel. Only of 13,322 39M and circa 8,000 - 20,000 (according to various estimates) 43M were produced, which makes it extremely rare and valuable among collectors.
Produced versions of Kiraly SMG included the variants Király-géppisztoly 39M, Király-géppisztoly 43M, Király 50M, and also 39/A M. (39M with folding wooden stock) and Király-géppisztoly 44M prototypes. From the early 1950s Kiraly SMGs has been replaced by PPSh-41 and Kucher K1 in the Hungarian army. The Kiraly 50M was made for the Ministry of the Interior and the Army did not participate in the development. The 50M submachine guns were used primarily by police, railroad and factory guards, probably until the late 50s when they were replaced by the above Kucher K1.
