I didn't find that mark in "The Standard Directory of Proof Marks", could be a manufacturers symbol? Hard to see though, next time dust it with cornstarch or chalk and then wipe it lightly.
Well this is a fine pickle we're in, should'a listened to Joe McCarthy and George Orwell I guess.
I would have guessed a proof mark as well. Not a standard Spanish (Santa Barbara) proof mark. Makers mark or gunsmith that did the work? Santa Barbara actions were quite common some years ago.
In 1970 I worked for Small Arms Manufacturing Co. In Bridgeville, Pa. We fitted our barrels to many Santa Barbara and Mark X actions. If I remember correctly we use a horse head stamp on the barrels. It is now Shaw Manufacturing. They may know.
Mike
NRA Patron Member
If its "Made in America", its not setting on a container ship!