For Czarist Russia to develop an early submachine gun some innovative military thinking is going to be required plus equipped large numbers of troops with a new weapon. Somehow I don't think that is going to happen.
If I remember it correctly, submachineguns weren't widely used by anyone except Soviet Russia before the start of WW2. Even Nazi Germany, which was normally quick to pick up on these things, only issued them in a 1 to 10 ratio.
Yes, I was toying with idea of Lahti becoming weapons designer in Russia. Problem is, his designs shared all the shortcomings of early SMGs (insane amount of machining making weapons waaay too expensive in mass production). Basically, mass-produced SMG should be made using stamping, as STEN, PPSh, PPS (actually better design than PPSh), and (to a lesser extent) MP-40. Using Lahti's magazine, however, is possible.The most likely SMG for a surviving Tsarist Russia would be the Suomi from Finland.
The sheer numbers of problems (what DID work in Czarist Russia?
"Ammo hunger" of 1914-1915 had been caused not by inability to produce and deliver cartridges and shells but by severe miscalculation of consumption. I don't remember exact numbers off the top of my head, but General Staff geniuses were requesting something like 500-1000 cartridges per rifle, amount which had been shot through in first month of war or so. By 1916 Russian factories produced as many cartridges as troops could consume and logistic system was generally adequate in delivering them to frontline. Besides, we're talking about WWII, aren't we? There are very conflicting POVs on how good or bad Russian Empire would be economically comparing to Stalin's USSR, but nobody seriously deny that they would be at least comparable. Besides, cartridges are kinda low-tech product, ideally suited for assembly on tobacco factories, for example. All in all, I don't see cartridge problem as the biggest.... it's an ironic suggestion, I'm afraid.... The greatest Russian failing in WWI (and there's plenty of competition) is that they ran out of ammo quickly, or like to my granddad, issued the wrong kind.
Generally, I expect rate of SMG adoption be somewhere below OTL Soviet level. There would not be whole regiments armed with them, SMGs would remain weapons of top 10% frontline troops (stormtroopers, squad commanders and such).I'd guess any Russian gummint would be slow off the block with them until production and supply started to be less than hopeless, as the Red Army was. And that'd be a good, long time unless there were some seriously amazing governmental reforms.
Yes, I was toying with idea of Lahti becoming weapons designer in Russia. Problem is, his designs shared all the shortcomings of early SMGs (insane amount of machining making weapons waaay too expensive in mass production). Basically, mass-produced SMG should be made using stamping, as STEN, PPSh, PPS (actually better design than PPSh), and (to a lesser extent) MP-40. Using Lahti's magazine, however, is possible.
Russian Army adopting anything equals "mass production", if you want this anything to be visible. And Lahti's designs (LMG, SMG, handgun) were not adapted to mass production. It might be consequence of industrial base he was relying on (basically arm repair workshops with fancy names of "works"), I don't know. But, assuming he understood mass-production technologies, he could use Swedish facilities, couldn't he? But he didn't. So, to be frank with you, I don't see him becoming a father of Russian SMG. LMG, possibly, although Lahti-Saloranta was a dud comparing to DP, for example (this is an off-topic, but DP is butterflied away too).The OP doesn't mention anything about mass production and in the period given, the 1930 to 40, Lahti's designs were the norm.