https://www.facebook.com/RoyalArmouriesMuseum/posts/10166176590150370

The interwar period saw significant developments in the field of firearm suppressor technology. Covert operations forces in particular proved keen to use this to their advantage during the Second World War, such as Britain’s Special Operations Executive.

... the carbine has been fitted with a suppressor to reduce the noise produced by its .30 in Carbine cartridge. However, the drawing also shows how the gas system of the carbine has been removed in order to accommodate the suppressor. The result is that this carbine is manually operated, the user having to work the action between each shot.

Whilst this may seem to be a drawback, the concept is sound as far as noise is concerned. In this case, the user can eject the fired case of their last shot at a time of their choosing, reducing the amount of noise and movement after their shot and also allowing them to easily remove the spent case from the scene.

WW2's got a bunch of cool suppressed guns, the Welrod, the De Lisle carbine, the High Standard HDM...