The M1 Carbine went to have a wide acceptance in ww2 and later, that probably have had a lot to do with it's qualities as a weapon of war and ability to be mass-produced, even if it was not a perfect weapon. So let's give the other their chance to introduce the M1 Carbine-equivalents, too, before their part of the war starts, and not just as a replacement for the service pistol for non-combat troops: Soviet Union, Germany, UK, Italy, Japan etc. Feel free to axe a concurrent project dealing with infantry weapon, so there is enough of designers' and engineers' time available, ditto for money, production line(s) and material. Job can start any time after 1935, with a cartridge powerful enough that can do the job ("invent" a cartridge where needed, with an eye for a quick domestic production of both barrels and cartridges).
Semi-auto limited, with option to go full-auto later. Weight of under 3 kg loaded, fires from the locked bolt. Fixed or folding stock. Effective range of 300 m, so don't go with a too short barrel and a too weak cartridge, either. Detachable magazine.
Semi-auto limited, with option to go full-auto later. Weight of under 3 kg loaded, fires from the locked bolt. Fixed or folding stock. Effective range of 300 m, so don't go with a too short barrel and a too weak cartridge, either. Detachable magazine.