Czechoslovak “aym” code, 1950s.
To add to Doc AV post,
aym = the manufacturer Povázské Strojárne Národný Podnik, Povázská Bystrica, Czechoslovakia
53 = 1953
… and to complete above details:
– (dash) = single Berdan primer hole
is it steel core?
This is my expectation, but I cannot say for sure. JonnyC, can you?
It’s tough with the Czech bullets. There is one lead core, and two steel core variations. I have never seen a reliable break-down on what goes with which headstamp.