For Doc Av: Both EC and ECS produced brass .45 cases in 1942, loaded at EC. EC also produced at least one lot of copper-washed steel case in 1943.
Twenty-round US Military .45 boxes predate the Thompson SMG or the use of any SMG by the United States military, going back to WWI and before, including the packaging for the M1906 .45 cartridge.
For Les et al: Production ceased in 1944 at Evansville Chrysler and Evansville Chrysler Sunbeam Plant.
Aside from the FA 4 06 and FA 4 08 cartridges, which are not .45 ACP case types, but rather both the 1906 case type, Frankford’s serial production seems to have started in September 1911 (F A 9 11) and ended in 1956. The last known FA .45 round to show the month of production on it was 10 17 (October 1917).
The last known Peters headstamp was from 1927.
Maxim only made .45 ammo for a short time (possible even that subcontracted out) with the earliest known date of 5 17 and the highest known date of 10 17. Headstamps with no month, just the year “17” are known with the date offset, as with a bunter that has had the month ground off of it, and with the date centered.
The earliest U.S.C.Co. date known is 3 13. The latest with month 7 17 and the then without month in 17 and 18.
Winchester used the headstamp “W” during WWI and headstamps of 17 and 18 are known. There was also a small lot headstamped “W.R.A.Co. 18”, very rare today, where a .30-06 bunter was used to stamp the headstamp. They resurrected the “W” headstamp in the years 1938-1940 on ammunition made for China, and perhaps other countries. They are very scarce as well.
Regarding the WCC headstamp, the earliest use of which was in 1941 with “WCC 41”, I do not know exactly what year it ceased to represent the Western Cartridge Company and became representative of the Wincherster Cartridge Company (Olin). The headstamp appeared in WWII with dates 41, 42 and 43. It was resurrected during the Korean War with dates of 51, 52 and 53, and continued on with the date 54 with dates as high as 99 (1999) known, although some dates from the year 1956 to 1999 are missing.
The first use of “RA” on .45 is R A 41 and continued with the years 42, 43. 4 (the single digit representing 1944 - ground bunters for economy purposes) and 45. There si also a “R • A 42” headstamp with dot representing a different case-drawing process. There was not dated “RA” production between 1945 and 1952, and then 52 and 53 dates are known. After that, the next known date is 60 with the last known date for the “R A ##” headstamp being R A 6 9. There is a headstamp “+ RA 70” probably made with a 7.62 NATO bunter (the “+” I thyped represents the NATO Mark of a cross within a circle, which I cannot reproduce here). In the WWI period Remington used the REM-UMC headstamp with dates know of 2-13, 17, 18 and 19.
I cannot mate headstamps to lot numbers on boxes. Someone else will have to do that. In my own collection, I do not collect dates on headstamps, only one of each style, and in boxes, I collect only physical and visual differences in the boxes, not every lot number.
Headstamps with the word “MATCH” or the initials “NM” were not considered in the above compilation.
Federal did not start producing .45 ammunition with military headstamp until 1953, so I did not consider them either. However, I might as well mention that they produced date rounds with the “FC” headstamp in the years 53, 54, 5 (representing 1955), 60-65, and again from 96-99. although that group include the caliber of “45 AUTO” on the headstamp and were probably actually made as Federal’s “Generic” (lower priced) offering on the civilian market.
Hope this is of some help, and not too confusing. The information was taken from my own collection, and then, for the major part, from the wonderful list of known .45 auto headstamps put out by Butch Daubner, the one used being dated August 20, 2009.