Hungarian Danuvia 39.M
Nicknamed the Király Géppisztoly (Royal Machine Pistol), this little-known Hungarian-made SMG is widely viewed as one of the best of WWII, and at least one source describes it as an intermediate step between the SMG and the assault rifle: the 39.M has the longest barrel of any SMG, providing better accuracy. Its sister weapon, the 43.M, was essentially the same weapon with a folding stock and a slightly shorter barrel. The gun is little known in the West; understandably so, as most copies were lost on the eastern front.