I got this case today in a bag of odd rounds, and I would like to know the calibre.
Headstamp is: “COLLATH FRANKFURT A/O TESCO”.
It is a brass rimmed case with brass cup Berdan primer, and a slight bottleneck.
Mouth Dia.: About 9mm (0.37").
Case length: 64.25mm (2.526").
Base dia.: Just under 13mm (about 0.51").
Rim thickness: 1.2mm (0.05").
Any info would be helpful.