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Given that war was likely, The Germans and Italians could have integrated their military industry and standartized weapons from 37 or 38, with mutual beneficts. German weapons being made in ataly replacing italian ones is easy, but what italian weapons should have been adopted by the Germans?
What an integrated OB would look like? A few ideas...
Small Arms:
Italians adopt 7,92mm for their rifles, start producing the MG34 and the P38.
Germans adopt the Beretta M38A SMG
Heavy weapons:
The Germans adopt the 149/40 Field Gun, the 149/19 Howitzer and the 75 Howitzer and 75/32 Gun. The Italians adopt everything else (AT Guns, 105mm; AA Guns, etc...)
Tanks
Easy, the italians start building the PzKfw III and IV from 38 and change versions with the germans
Aircraft.
The MC202 would be avaible earlier, the Piaggio P108 would be built in germany and the Re2005 could replace the Bf109 from 42 as the standart Axis fighter aling with the Fw190.
There is a lot to elaborate from here, with a PzIII equiped Litorio and Brescia Divisions being much more capable, the Cr25 being built in German versions, the germans learning the advantages of diesel engines...
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