Is it just me ... ?

[butlersrangers]

That is very neat 'Parashooter'. Thank you for sharing!

I wonder when this 'work holding fixture' came into use? (I wonder how things were done from 1894 to 1904)?

With this fixture, one operator, doing 120 serial numbers per hour, would average 30 seconds per action, in 1917.

The operator would have to 'clear' the fixture, lock an action into place, properly index the action, andwork a handle to ratchet feed the work through the fixture as a six or seven digit serial number was hand-stamped on the receiver. (If I understand correctly).

I can see how the depth of numerals might vary, depending on force of the hammer strike.

If the digits were done one at a time, I am guessing there would be some 'screw ups' and mistakes.

Seeing drawings of actual tools and fixtures (and trying to comprehend the function) is quite interesting.

[FredC]

The spacing with that fixture would be pretty good. The one they used in the 1890s might not have been as good. Also the individual stamps might not have been perfectly centered. Not sure if they used a press or spring loaded hammer like todays automatic center punch to get consistent depth. I am sure the stamping was done before heat treatment (case hardening). If they spoiled one during heat treatment, I guess they could have reused the number to avoid skips?
As stamps wore the numbers would be come more blunt and change shape slightly. they could have chipped before anyone noticed then your 4 could look like a 1 till it got replaced.

[butlersrangers]

From the 1916, "...Specifications Governing the Manufacture and Inspection of the U.S. Rifle, Caliber .30, Model of 1903...":

".... The receiver, of forged steel Class C, is drop-forged and annealed before machining. On the upper surface of the front end is stamped the serial number of the rifle and the place of manufacture. ...."

[reincarnated]

I am amazed that the numbers are as even and uniform as we find them today. Has anyone ever found duplicate numbers? Human beings, being error prone even back then, did make mistakes.