I can't say for sure, but this is possibly one of the sub machine guns that has endured through time. Production began in 1931 and it was still in use till the mid-late 80s is a pretty good track record for a firearm. Sadly it's a neutered semiauto and got an extension on the barrel to meet ATF laws, it's a TNW parts kit build, and thankfully it's been problem free. It will eat everything from WWB to hot NATO ammo, even the 9mm +P+ stuff hasn't phased it. Recoil is none, zip, zilich.
It's a beast, it easily weighs what a Garand does empty, with no mag, with a loaded drum, 71rds of 9mm, it's pushing 16pounds. This became the equalizer during the Winter War against Russia, and inspired many different designs. True to Finn design, it's built very well, and highly accurate. The stock is an early original Finnish stock, and is tiger striped, I do keep a newer version stock, similar to the M39s for shooting, and the drum shown is not the greatest, I didn't get the others out, this drum misfeeds about every 7th round, and mainly gets used for display. The two other drums, feed with no issues, after winding the spring up and tons of cleaning. The stick mags are 36rd, and the haversack is of Finnish military origin as well, with the typical [SA] stamp