Thanks for the info, TonyE.
I looked at my Laidler Sten book, and he did not cover ammunition. Iannamico covered ammunition in his Sten book from a current U.S. NFA shooter perspective. David B. Gordon, in his book, “Weapons of the WWII Tommy” showed several examples of regular ball ammunition, as you mentioned.
I suppose I could add context to this question. The person who posed the question limited his query to WWII, because he asked about a Sten magazine marked with an “S” on its body, found in a French Resistance weapons cache about 15 years ago. His hypothesis is that it could indicate ammunition for a suppressed model. A UK member chimed in since I initially posted, and he thought it was unlikely the marking indicated such. He stated, “However, I can’t vouch for the SOE Silenced STEN with the CISA silencer so its possible that other, non standard contract 9mm ammo may have been purchased for these (But I doubt it).”
Anyway, it looks like the magazine body mark representing a suppressed ammunition loading is conjecture at this point.
Here’s the link to the thread, if you have any interest…
machinegunboards.com/forums/ … opic=16012