ERMA made MP43, MP44, StG44 barrels and letter block

I’m looking to see if anyone knows any info on the Erma made barrels that they used on their MP43, MP44, and StG44 rifles. The barrels had their maker code “qlv” followed by a letter. An example is on an MP43 made by Erma, the barrel marked qlv followed by the letter “S”. Then on a late war 45 dated StG44 the following….qlv “V”. I’m assuming this is a lot sequence? If anyone knows any information on this particular maker, I’d love to know.

There was just a giantific book series on Erma published last week, maybe that has the answer for you? https://www.amazon.com/ERMA-Erfurter-Maschinenfabrik-1924-2003-Submachine/dp/0764368559

Yes….i saw those….but if you look at the three different volumes….none seem to cover the MP44 series of guns.

"qlv" is the code for Erma at the end of the war.

Yes, you are correct. So, qlv (Erma) then the letter “S” or “V” must just be a lot designation or associated with a time period of manufacture??