Mayhem - Thanks for the HWS reference. I had not read it in a long time. I do not believe your cartridge is the one described as the T29 “all brass” round made experimentally by using a brass extension tube loaded in the case (headstamped RA 42), which is the cartridge referred to in Fig 18., although I believe, from what is in the text, that the caption of Figure 18., which shows the headstamp of Cartridge “A” as “R A 42” and that of Cartridge “B” as “R A 4,” is erroneous, reversing the headstamps of the pictured cartridges from those as described in the text above the picture. This is, by the way, if I am interpreting it correctly, the first time I have found an error like that in Frank, Bill and Gene’s book. I believe that your very good picture shows a case that is one piece, not an inserted tube, from top to bottom. I also think in figure 18 that the overall case length measurement of cartridges “A” and “B” are reversed, as the drawings are to the same scale, and the Cartridge “B” is clearly longer than Cartridge “A”, even though the supplied measurements would indicate the opposite. (in truth, it is likely that it is the cartridge drawings that are reversed).
When it gets into the second paragraph of the same page, but the column to the right, about "The T29 cartridge as finally developed...." there is another entry that confuses me, as it describes an overall length of the cartridge on production drawing of the M15, from March 6, 1944, with an overall length of 1.265 - .030. I don't know what that second figure (.030) means, and it is not explained. If what appears as a dash is actually a minus sign, that would bring the OACL length down to very close to the one I measured, but if it is a dash, I haven't a clue to what it refers to.
I think that first, we need an OACL for your cartridge, and second, we need a picture of the over-shot wad to determine the exact color. “Red” can cover a lot of shades, and it is not one of the colors mentioned for experimental rounds in HWS II. If purple, bright or faded (where it could take on a reddish look), that would insure your cartridge is a production round).
I do appreciate your supplying of the HWS page and illustration number. It made this easier to evaluate.
P.S. While I was typing this Pete de Coux supplied a comment, which I can’t read as I type this. I will go ahead and post this, but it may duplicate things Pete said.
O.K. Pete noted the difference in the addendum, which I did not have at hand. I suspect I must have it in my library, but didn’t grab it when I brought the book itself up to my office. I see it validates what I said about “reversal.” Thanks’ Pete.
Edited to include the last paragraph.