When you try to introduce new small weapons, you need to decide what ammunition you are going to use.
I think that Poland would accept 9mm Parabellum as its basic pistol cartridge. Good, reliable, and already produced in pre-war Poland.
So what would be shooting it?
Vis as a basic pistol of the Polish Army is possible, at least in the beginning. I think it will be replaced rather quickly with newer model, with bigger magazine, something close to Browning HP or CZ-75. Let's call it Vis-2.
I have my doubts about Polish Army using two very different submachine guns the same time. When you have one decent model, you do not need more - it is expensive and makes training harder. While a new Polish construction is possible (although Błyskawica is pretty much modified Sten), I think there is a big chance for licensed production of Czech Sa-23, a very good weapon available from 1948. Would the Poles want to wait for their own construction until 1951 to introduce Błyskawica-2 or until 1957 for Storm? Especially if Storm is so similar to Sa-23?
Rifles.
The basic weapon of any army. I do not see the decision being postponed for long, especially with all the rifles in the Polish inventory using various ammunition. It would be a very bold move, but if people like Roman Korsak or Kazimierz Januszewski (Stefan Kenneth Janson) return to Poland in 1945, something similar to EM-2 might be created. If the Polish authorities prefer something more conservative, I think Jerzy Maroszek could help, perhaps with something like Polish equivalent of FN FAL or German G3? Or perhaps Soviet influence would win and a weapon similar to AK-47 would triumph, like in Finland?
Each choice requires a different cartridge: British .280 (intermediary), Czech 7,62x45 (intermediary), American 7,62x51, Soviet 7,62x54, Soviet 7,62x39 (intermediary) etc.
The choice will influence tactics or tactics will influence the choice. I mean what will be the future war according to the Poles?
A new school option: Poland decides to go with an intermediary cartridge (British.280, Czech 7,62x45, Soviet 7,62x39) and introduce something similar to EM-2 (or AK-47), with light machine gun as infantry squad weapon (something like Czech vz.52) and MG-42 recalibrated to 7,62x51.
Conservative option: Poland goes NATO way: a rifle being an equivalent of FN FAL or G3, with MG-42 as both GPMG and squad weapon.
My gut tells me Poland would go conservative way, OTOH the British were also considered conservative and yet they went with EM-2 and only pressure from US forced them to change their mind.
So let's be bold.
Poland introduce their own rifle for Czech intermediary cartridge, lets call it "Burza", (Tempest) together with Czechs introduce light machine gun based on ZB-26 (an equivalent of OTL vz.52) and decide to copy MG-42, only recalibrated to 7,62x51 cartridge (when Germans protest, Warsaw declares it part of war reparations).
As for MP, I decided that they could go the route of a more ambitious project like "Burza" and a cheaper alternative like Błyskawica-2. In case the "Storm" was too unreliable or had an excessive rate of fire like the progenitor MCEM-2. It's still the 1940s and 1950s, where there is still a strong emphasis on the development of domestic structures.
Additionally, the introduction of Błyskawica-2 allows for the faster withdrawal of Stens, PPsz, MP-40s and Thompsons.
Of course both use 9x19 Parabeulm. Because it is already produced in Poland, and the Vis was still produced by the Germans, so the ammunition for the new MPs is already available.
As for automatic rifles, I think that the Armed Forces would organize a competition for a new weapon, sometime between 1953-1958. The choice would be between the FN FAL, M16, AK47/AKM, or some domestic proposal.
The AK-47 would probably win for several reasons.
1. It is cheap to produce
2. It would be possible to settle accounts with the USSR using barter.
3. It would also be an element of the policy of neutrality
4. The USSR itself can provide several thousand pieces ready for training.
Although I might put it to a vote.
I agree with the idea of the vz.52, it is a good solution and does not violate national interests.
As for the doctrine, for now it is purely defensive and rather prepared to repel aggression from the East. However, for larger funds, the army will wait until 1954, when conflicts on the West-East line begin to break out in Asia and the division of Austria becomes permanent.
I wonder what is the like hood of Poland cooperating with Czechoslovakia (Or just Czechia in this case?) to build Me 262 clones? Or rather, to build improved copies of the Jumo 004 jet engine.
As for tanks, it will probably follow a similar path as with the French and their AMX M4/50 program, mostly based on WW2 German tech with refinements here and there, and in Poland's case, no oscillating turret but a regular, perhaps, Tiger II turret? The long 88 could still be effective up to the mid 50s without ammunition improvements, to the 60s with.
Only 12 Me-262 clones were built. Warsaw can experiment with them, but they will probably only be single pieces.
For now, most of the funds are spent on reconstruction and new factories. Especially the implementation of the Citron 2CV and H licenses. These are to finally drive the Polish society and also the services.
In addition, the STAR truck factory, buses from Sanok and the reactivation of LRL plants in Warsaw and Lublin.
As for tanks, I assume the purchase of AMX-13 to retire Crommwelys, Stuarts and T-70s. The construction of the AMX-13 will also enable the construction of many specialized vehicles and will also be used to train engineers in vehicle production.
