Identification of unknown 13 mm case

Dear forum,

I have been trying without succes to identify this case that looks a bit like a longer .50 cal case. It measures, for as far possible considering the damage, 13x133R22 mm and there is no visible head stamp.



ps. I would like to add images but I do not know how and I have no time to figure that out. Will add them later.

Here’s the BOCN link, hope it’s OK: … 13-mm-case

The pictures:

Thanks for posting the pictures for me!

On WK2AMMO a collector from Czech mentioned it is most likely a Czech per-1940 experimental anti-tank gun case, where many developments were ongoing in calibers of 11 mm and 12 mm with different case lengths. I will check after work if I can get a better estimate of the caliber.

[quote=“clieuwens”]The pictures:


The damage to the side of the case looks as if somebody used it as a target for shooting an air gun.