What weapon, designed by Aimo Lahti, was a descendant of the M-22 prototype and the KP/-26 production model?
Aimo Lahti Aimo Johannes Lahti (April 28, 1896 – April 19, 1970) was a self-taught Finnish weapons designer. Of the 50 weapons he designed, the best known is the Suomi M-31 SMG. Other well-known weapon designs of his include the Lahti-Saloranta M/26 LMG, Lahti L-35 pistol, and Lahti L-39 anti-tank rifle. Lahti also designed the 7,62 ITKK 31 VKT anti-aircraft machine gun and the 20 ITK 40 VKT anti-aircraft cannon.
RPD machine gun The RPD (Russian: ручной пулемёт Дегтярёва "Ruchnoy Pulemyot Degtyaryova", English: Degtyaryov hand-held machine gun) is a 7.62mm light machine gun developed in the Soviet Union by Vasily Degtyaryov for the intermediate 7.62×39mm M43 cartridge. It was created as a replacement for the DP machine gun chambered for the 7.62×54mmR round. It is a precursor of most squad automatic weapons. It was succeeded in Soviet service by the RPK.