Denims, etc

Ed,
That's been my question as well. I would suppose that any changeover would occur as existing stocks of fabric were used up -- explaining the two different fabrics so close to each other, date-wise.

The actual denim fabrics appear identical in weave/weight.

The green jacket shown isn't mine. It's a photo I saved some time ago. I have one of these but the date is washed out -- just a faint trace of the purple stamp.

David brings up a point about the black inspection/acceptance stamps. I don't know how to decypher these. I would think that every inspector or depot had their own stamp? Does anyone have a way to decypher them? I'm positive they have no relationship to month/year since my 1941 example has "725" on it. No idea what the upper letter represents. My '41 denim has an "A".