The 7-57 has the digit 7 in it's name twice. Other than than it's just an old cartridge that some folks talk about.
I just looked to see that I have one. It's an old ZB Brno 22 H with a 20" bbl, m70 type 3 position safety, scoped with a Vari X 3-9 Compact in a zb slide off top mount.
