My earliest M39 load, with no seals or purple seals, is from 1942. It is from AmF 24 (also from “M”) and undobtedly exists with a 1941 date also, probably missing from my collection only because I don’t save all dates, since I have a blank and a dummy with AmF 24 headstamped dated from 1941. My latest M39 load is with green seals and is from 1986. These rounds weigh (complete cartridge) just over 180 grains. The M39/Bs, which have an overall cartridge weight of about 170 grains (some a little more, some a little less) run from Karlsborg in 1953 up to 1990 with red seals. I have a round with the CG headstamp from 1906 with red seals (nickeled-cup boxer primer) but it weighs 176 grains, awfully heavy for an M39B, taking on more than half the difference between the older M39Bs and M39 rounds. I don’t know if it is technically an M39B or not. Unfortunately, most of the CG headstamped rounds I have are in contract boxes for other Scandinavian countries, not for the Swedish military, and the boxes do not show the M39 designation in any form (M39, M39/B, etc).
All of our Swedish collectors seem to have disappeared, so my collection, which used to be pretty good, pretty much died in the late 1980s. I still have some, like I said, contracted in Sweden for Norway and Denmark, but nothing from Sweden itself.
I believe the earliest M39 rounds were from Germany. The headstamp B DWM B 480C seems to play heavy into Sweden with the contract of Model HP (P-38) pistols delivered in 1939 to Sweden and given that year-model desgination by the Swedes. I have three variations of Swedish dummy round with that DWM headstamp. There is also a scarce headstamp “2 DWM 40 B” my specimen of which came from Sweden, and I suspect the headstamp was made for them.
There is also the headstamp NORMA 9mm M/39, but I am not sure whether that is pre-WWII or post WWII. I suspect it is the latter.