The Russians really like their PPSH41 with 71 rd drums. manufactured almost 5 million of them by 1945. Years ago, I saw a North Korean copy of the PPSH41 and dated 1952. The PPSH41 drum
is strong and appears to have been well liked by the Soviets. GermanWW2 captured examples were converted to 9x19mm with MP40 magazines, but many were not altered, just used as they were
found/captured.