Interesting points on the production dates, but still conjecture. One could argue that there was no reason to change the date at all (I don’t agree with that proposal, by the way).
Is there any proof that this is ammunition that was used in the Carribbean Legion’s 1947, 1948 and 1949 “endeavors?” There was not shortage of foreign 9 mm ammunition around the world in those years, and the use of any ammunition not of American manufacture would have served the same “alibi” provision as purchasing new lots of ammunition with a nondescript headstamp and phony date.
In fact, is there any proof that this ammunition was ever used by the so-called Carribbean Legion? I am not saying it was not. I simply don’t know, and in all the research the two of us have done on this ammunition, I have not, to date, seen any evidence that it was used by the Carribbean Legion, or for that matter, that it was not used by them. These cartridges have been found many places - SE Asia, southern South America, on the US surplus market, etc.
Regarding the change of the bullet jacket, lacking documentation, one would have to wonder why Canada changed the bullet material on their properly-headstamped, Canadian issue ammunition from GMCS to GM. Since we have not “regular” issue Canadian military 9 mm between the years after 1945 and before 1955 with which to compare to the clandestine headstamp, again, we are left out in the cold for knowing precisely when the “9 MM 40” and its full date sequence were made. A simple code of a single-number change would be an easy and sensible thing to do, and the huge quantity of this ammo that showed up on the US MILSURP market, not to mention around the world, would not rule out six years of production. The sequence of magnetic and non-magnetic bullets (“40” always magnetic, and while I don’t have one, I understand that “41” is found with magnetic bullets as well as the non-magnetic one of my specimen) would fit very nicely into the possibility of the dates of 40 thru 45, actually representing 50 thru 55/
Of course, all the opinions I have expressed are also pure conjecture. All inquiries I ever made to Canadian contacts brought back either the answer, “I don’t know,” or “they are not Canadian” (silly answer in my view), or “the dates are the actual dates of manufacture,” also silly, since it is well known that the 9 mm was not produced in Canada until 1942. I am sure that some of the answers received were sincere, and that many others were made as perhaps the subject was “classified” under Canadian laws or factory policies.
I doubt we will never know the full answer for this unless government records in Canada and/or the USA are released as public information at some future date. I doubt that will happen for a number of reasons that don’t need discussion here.
For all the arguments and information see the referenced previous thread on this ammunition, with the link shown by “Ordnance Guy.”