"...to the left is an "eagle-head" over a date of manufacture (in this case 1929)..."

Onefastokie,

Thanks for the great wrap up. This info would be of great help to others, I'm sure. Not everyone would have such an appreciation for the details as you've presented. Well done.

A query that bothers me that you might be able to assist with: The US only made the P14 and M1917 between 1916 and 1918. At the end of WW1, the M1917 was considered obsolete and stored as a second line reserve. That makes me wonder why there would be a mark suggesting a manufacture date of 1929?

Could it be that these eagle marks are:

1. annotated with the Inspector's personal ID number (hence, this bloke was "Number 29" in the Remington factory, or
2. that the date of inspection was 1929, for whatever reason the bayonet was being assessed within US service?

Curious, your thoughts would be most helpful on this.

Thank you again.