The Skorpion Machine Pistol was invented by Miroslav Rybář as his graduate thesis for the Czech Military Training Institute, and it has changed very little from its original design. The gun was adopted by Czech security forces in 1961 and saw service until 1979. Also known as the Vz 61, it is chambered in .32 ACP and feeds from detachable box magazines, is equipped with a folding buttstock and could be fired semi-automatic or fully-automatic. The Vz 61 Skorpion is not legal in the United States due to the National Firearms Act and import bans, however, they are gaining popularity in the U.S. with a version on the market that is a fully-legal semi-automatic-only pistol. For more on the Czech Skorpion Pistol, watch this "I Have This Old Gun" segment from a recent episode of American Rifleman TV.