winchester receiver markings

I'm a newbie, so I can't answer the actual question. However, I can add a similar data point. I'm also interested too in what some gurus have to say on the matter.

I have what I'd consider similar marking on my earlier made spring tube WRA receiver in about the exact same place as yours. I can only guess as what letter, symbol, or number they are as the artifact mark doesn't seem to pressed evenly or deeply when it was originally done. To me it's two symbols for sure, and I'm guessing one's a "4", and one's a "D".

These are markings used by manufacturers for internal purposes known only to them. Possibly inspector's marks. Inland has the most well known referred to as "Inland Hieroglyphics" located on the flat of the barrel near the receiver.

That didn't take long, thanks Jack!

I've seen pics of the Hieroglyphics on Inlands, those are wild. I bet one day somebody will uncover a document/s that says what some of these internal coding marks meant.

Then this was waiting for me at home.... new old stock sealded m4 bayonet