Identification ammo 18, 19 - 20 mm - 2 cm?


I find this case.

there are no marks or stamps on the base.

What is it ?

Pictures and draw :


This looks like it could be a Russian or Eastern Bloc 12.7 x 108 Case modified to chamber in a shotgun. This could have been done by someone who did not have access to factory made shotshells.

The outside of the case looks to have been filed down, while the rim has also been modified. To me it has a “home-made” look to it.

I have seen photos of similar shotshell cases made in Italy after WW2 from 12.7 Breda cases.