the owner of this double needed more brass and what was laying in my reloading cave for many years now?

made from 20x99R a WW 2 sovjet aircraft canon cartridge here for comparison with a 50 bmg case, than a eley 10 ga brass case and my homemade brass

bought the 20x99R once from a metal detector guy who pic them up from battle field
to bad most of them had dents maybe from the action when ejected but I made the best out of this.

because of the big berdan primer I drill them out and set a 38 special case in , then late turn the base. must be drilled for a shot gun primer.

the 38 special case was cut to 10 mm and rivet inside