I came across this document on the Remington Collectors Society.

http://www.remingtonsociety.com/imag...nd_A3-2005.pdf

It lists production rates per month , and months off acceptance / buy off from the gov't.

And it goes on in the notes to explain s/n problems and select batches of s/n's for a4 variants and such.

It seems the "s/n's by the end" of the month is nothing more than a calculation that, not done by records, and the calculations used some assumptions.

Other columns track the production rate by month, as well as by acceptance/buy off.

If you go by production rates, one can more figure closely to within a month or two the born on date . The document goes on to say that after final rifle assy, then the receiver was given a s/n... and there was a 2wk delay there.

So using the 1st column in the document, within a month or two, you can get a better idea of born on date.

So it seems for my s/n, this document agrees with a different list, that didn't go by month, just year which included my s/n as a 42, rather than a 43 rifle.

This list will bring me into Nov 42 or Sept42 for a born on date, rather than Jan 43.