The Vigneron was Belgium's standard submachine gun during the early years of the Cold War. It was originally adopted as the M1 in 1953, and about 21,300 were made. In 1954, several modifications were made, resulting in the M2 pattern. Many of the original M1s were converted to M2 specification, and subsequent new production was of course in the M2 pattern. The specific changes were:

- A protective hood was added to the front sight
- The spring catch for the ejection port cover was redesigned and strengthened
- The rear sight was changed form an aperture to an open notch

And, of course, the magazine well markings changed to indicate the new pattern. Because of the upgrades made to existing guns, M1 pattern Vignerons are pretty scarce today. Many thanks to the Royal Museum of the Armed Forces and Military History in Brussels for giving me access to film this one for you! Check them out here:
https://www.klm-mra.be/en/