Bergmann MP 28s 7.63×25mm Mauser (export) / *
The MP 28 is a recoil loader with a bolt and wooden stock. The barrel is surrounded by a perforated barrel jacket. The double-row rod magazine holds 32 rounds. The magazine well is on the left, the ejection window on the right. In contrast to the MP18, single fire can also be fired. The fire selector switch is located above the flue. The weapon, which is otherwise very similar to the MP18, can thus also be visually distinguished from it.
(7.65×21mm Parabellum - Wikipedia) (export)
SIG Bergmann 1920 [7.65×21mm Parabellum]
The M1920 was a basic blowback-operated submachine gun copied directly from the MP18. The only difference in design was the straight magazine feed, as opposed to the MP18’s backward-slanted magazine port, and the replacement of the MP18’s fixed rear sight with an adjustable tangent sight. The M1920 generally also used a more rounded cocking knob compared to the MP18’s curved handle. The M1920 did not take the 32-round “snail” magazines used by the MP18, but instead fed from more conventional 50-round double-stacked box magazines.
Pistola-metralhadora 11,43mm m/935 . 45acp
Portugal bought in small quantities of the .45ACP version in 1935 and embraced it as the Pistola-metralhadora 11,43mm m/935. They also purchased a small amount of the S1-100 in 7.65x21mm Luger in 1938 and this was adopted as the Pistola-metralhadora 7,65mm m/938 Steyer submachine gun.
Dual-Magazine MP40/I
These guns are generally referred to as “MP40/II”, but this nomenclature is incorrect. In official Wehrmacht equipment lists, they are called MP40/I. There were changes made to the standard MP40 early in its production (new bolt handle design and ribbed mag housing), but these changes were never given a new designation. So the first major variant of the design was this dual-mag system, hence it was called the MP40/I.
With german SMGs only having 20 and 32 round 9mm adding 40-50 round smgs would help germany a lot against the ussr, funnily a ten round mp18 exists though what good it would be is doubtful.