If I remember rightly, from Phil B.Sharpe’s Military reports on German ordnance manufacture, the “Case Lot size” for Rifle cases was around the 180,000-200,000 unit mark, and that for 9mm P cases was about 230,000 to 250,000. That was the tolerance limit for the drawing dies
for case manufacture ( made of Forged and hardened steel); Case filling Lots were usually the same, unless the Lot was a special one ( such as Aircraft “Specials” etc).
In Case manufacturing, the various dies, Bunters, headstamps, etc , wear a different rates, and juggling the whole tool series for economic production causes some variation of Lot sizes, especially with Steel cases; of course, as the Smaller size dies get worn, they are ground out to the next size, and so on. Germany pioneered the “Two-die Draw” for rifle cases, reducing the number of draws from 4 to 2, even though in some cases the “Two” draws, was actually a “four”, but in Tandem
( ie, one machine did two (diameter) draws, one after the other in line.)
This method did cause some problems in case failure by over-stressing, but in wartime, this was acceptable, given the Millions of rounds produced.
Despite the detail Sharpe’s Reports go into, there is still loads of information waiting to be translated in the accumulated archives at BundesArchiv, Koblenz, since they were returned by the USA (Mostly Unread) in the 1980s…of course the (Polte) Archives taken by the Soviets at places like Magdeburg, etc, are still in Russia. These hold the whole history of the development of the 7,9x33 PP43 cartridge. ( Even though some snippets…such as Telegrams with results of field trials and improvements have surfaced in British Documentation.)