Russia first encountered submachine guns during the 1939 war with Finland and developed a healthy respect for the weapons. In a tactical sense they boosted the short-range firepower of armies, but in the war between economies, the SMG was cheap and easy to produce, so suitable for bulking out more expensive equipment in mass forces. Russia had started the war with the PPD-40 evolved from the PPD-35, a fine weapon that clearly showed its ancestry in the MP-28 and the Soumi, and that was the problem. Its hard to call any Russian small arm luxurious but the PPD came close by 1940s SMG standards.
Re-engineering it for ease of production became an urgent priority with the first Panzer rolling across the border, and the happy result was the PPSh-41. This weapon retained the PPD-35s good features and dispensed with those Russia could no longer afford. As such it was a curious mix of the old fashioned with the starkly modern, pressed steel combined with the sort of woodwork abandoned in other countries. It was chambered for the 7.62x25mm Tokarev round, the weapon being fitted to handle either a 71-round drum magazine or a 35-round stick magazine. Great stress was placed on making the weapon easy to produce. The PPSH was crude but effective and was suited to production in relatively primitive building plants, factors that went far to offset its many problems. Many PPSH-41s were built in backstreet engineering units and such things as standardization or parts interchangeability were nominal at best. Throughout the 1941 - 1943 siege of Petrograd, PPSH-41s were churned out in large numbers by the most unlikely of production facilities.
In 1943, the PPS-43 was introduced. This was even simpler and cruder than the PPSH-41 and featured an all-metal folding stock rather than the wooden stock of the PPSH. The metal stock made it unpopular with troops who disliked having their faces frozen to their weapons and the PPSH-41 remained the preferred SMG. The great importance of the PPS-43 was that it was made in one of the new production plants being assembled around Khabarovsk. A prefabricated factory complete with powerhouse and production line to build PPS-43s to the best of American manufacturing technology, the Khabarovsk No.5 plant came on line in Feb/March 1944 and started churning out PPSs like peanuts. Alone it was capable of making almost 30% of the then existing annual Russian production of this weapon, and Khabarovsk No.2 that opened up four months later could do the same. Better yet the quality of these new weapons was a mile ahead of the contemporary Russian average. This left the Russians with something quite precious, an oversupply of both weapons and manufacturing capacity. Unfortunately the bulk of this excess capacity wasnt good for much other than making more PPSs, but it bought time for the development of something much better.
By 1945, the Germans had introduced their StG-44 and the Russians were looking for a weapon to counter this rifle. They took the basic PPSH-41 and improved its engineering, using the industrial expertise imported from America to produce a truly mass-produced and standardized weapon. Raising the breech pressure of the 7.62x25 round well above 40,000cup increased the muzzle velocity from 505 meters per second to 550 meters per second while the old 5.5 gram bullet was replaced with a 7 gram one. This certainly gave the PPS-45 a lot more poke at long range. The barrel was lengthened to 16 inches, a new wooden foregrip fitted and the mechanism beefed up to handle the 7.62x25mm round. With the added weight of the longer barrel, forearm and beefed up bolt made a far more controllable weapon as a carbine. But the bolt wasn't that heavy nor was the stronger mainspring that much stiffer, and so in full auto the rate of fire was frightening.
The new 7.62x25mm cartridge, became known commercially as the Tokarev Magnum, bore much the same relationship to the old 7.62x25mm as the .357 magnum did to the .38 special. It was much too powerful to be used in pistols but it worked well in the new submachine gun. The new weapon was designated the PPS-45 and it quickly found its way into the hands of the troops where it became a much sought-after weapon. Its 71 round drum magazine gave it a significant advantage over smaller magazine capacity weapons. The lengthened barrel increased the sight radius, allowing more accurate fire while the PPS-45 also featured a bayonet mount under the barrel. It remained the standard submachine gun in the Russian Army until it was replaced by the AK-47. Even after that point, the PPS-45 was issued to the Russian police and it can still be seen today slung over the shoulders of policewomen directing traffic. The PPS-45 was widely exported and made its mark as a militia/police/paramilitary weapon. It remains in production today by the Schpagin Corporation, primarily for export purposes.
The other sub machine gun to find its way into Russian use was the Capsten. In 1940, the first wave of semi-official refugees after the Coup. Unofficially dubbed the Brain-Drain these people were selected or selected themselves as being of use to war effort and the Dominions and snuck out, usually though Ireland. Among them were number of small arms designers from Enfield and the commercial world who had some interesting things in their luggage. One was a set of plans for a very cheap emergency-production submachine gun named the Sten Gun. This was a crude and simple weapon made largely from stampings and chambered for the 9x19mm cartridge. The Candians put the project to one side for a while and only revived it when the war in Russia broke out
The Russian Army was demanding sub-machine guns at all costs and the Sten gun seemed ideal for their needs. By this time, the Russians were also placing orders for the 7.62x25mm pistol round with Canadian factories for their PPSH so adopting this caliber for the Canadian produced Sten gun. By this time, the Canadians had refined the weapon substantially as the Capsten (CAnadian Produced STEN), the Capsten Mark I being the original version in 9x19mm. This was rechambered for 7.62x25mm as the Capsten Mark 3 and was adopted by the Canadian Army as their standard submachine gun as well as being supplied to the Russians. By this time, the Mk.3 had been based around a length of seamless drawn steel tube, that was machined to cut various holes in it and threaded. Before having other components like the magazine housing, sights, barrel diaphragm and trigger group welded and pinned in place. The whole assembly then fitting into a wooden stock based on the Lee-Enfield to produce a weapon that looked remarkably like the Lanchester, that was to become the trademark of the British collaborationists. This was too complex a weapon and it was dumbed back down again, replacing the tube with a stamped sheet steel jacket, and came to resemble nothing so much as a PPSh with a side mounted magazine. This became the Mark 4 and was every bit as good as the PPSh, it was a little lighter, just as accurate, equally reliable and of course it fired exactly the same ammunition. The Russians were beating down the door clamoring for all that could be produced, and the Americans were waving their checkbook in support.
In 1946, the Canadians produced the Capsten Mark 6 that as revised along the lines of the PPSh-45, gaining a 16 barrel, the modified sites from a No.4 and being retuned to take the new high-pressure 7.62x25 round. The Capsten was never given the separate striker that allowed the PPSh-45 to be so accurate, but the Capsten Mk.II did regain the stiffer tubular receiver of the Mk.III Sten and the general level of quality had been steadily rising. This version also serving in both the Russian and Canadian armies, the latter designating it a machine carbine rather than a submachine gun. As a side issue, the decision to adopt the 7.62x25mm for the Capsten also meant that the Canadian Armys long-awaited semi-automatic pistol ended up as a Browning Hi-Power chambered for 7.62x25mm.