I have been told the "O" in the center above the sling swivel is SA and a "C" in the same place is WRA. I have also been told the off center hole is Winchester. The small letter markings on the inside corner is supposed to be WRA. Your ferrule has the Winchester off set hole and letter, but also has the SA "O" mark above the sling swivel, so somebodies information is wrong. They used to think the ferrules without the hole were early SA but then they started showing up on some of the Greek Collector grades HRA's. The published information is conflicting so I wonder if anyone really knows.
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