I think in the cross sceptre mark Salopian. It looked like 1 0 to my tired eyes hence the date mix up. I think it might be Z C as Gunman says. The 2 3/4" proof will apply to CIP proof compliant ammunition as per that sold in Europe. I don't know if U.S. 2 3/4" ammo is of a higher pressure or not. Lagopus.....