If you don't see any chamber marking then it should be 2-1/2 or 65mm.

Mine is 65mm and stamped Emil Kerner, which I found out was a retailer in Germany, much like VL&D or A&F. Uhlig may be too. Mine has agreener safety, but no clips or crossbolt and modest engraving. I needed a longer LOP so I'm adding a leather pad.

Good luck, I hope it works out.

My problem lies in reconciling my gross habits with my net income.
- Errol Flynn