The Standards cartridges surface from time to time, and occasionally can be found in full packets.
I was of the opinion they were used to act as the bench mark against which normal production was checked, which is correct.
I don’t have any records about production numbers, but always thought it would be relatively low, although during WW2 the dates include another number which would indicate a lot, either the month, or just a lot number.
Trying to sort some of my records I came across the attached document which may explain why this particular headstamp hasn’t surfaced. The S.A.A.F noted, as most are aware, stands for Small Arms Ammunition Factory, most likely at Footscray. Unfortunately it doesn’t make it clear if the monogram was MF (likely) or MG, both factories having made .303 Mk VII Standards during that period.
To undertake this exercise on Machine Gun barrels it was obviously useful to employ rounds which would all have the same characteristics, to minimize the chances of random results.
I also found it of interest to see how many rounds were used in this test. At least 612 used with the new barrel. The nickeled barrel quantity is not specific, nor is the C.C, barrel quantity, but I am guessing it would be in the hundreds.
If anyone has this particular round, or a photo of the headstamp I would appreciate a copy.
This headstamps show the layout used when there was more than one lot in the year during WW2. I also don’t know if the MG type always used this date layout. Any information would be most welcomed.