Update - This is in Pete DeCoux’s current auction
I have one case-drilled and primer-struck as yet unknown cartridge for sale. It is a 50BMG case with an FA51 headstamp and a typical steel core M2AP 30cal bullet. For testing, or penetration or wound tests? Who knows… This cartridge is very close in dimension to the 7.92x94 German cartridge, but it differs in the neck length proportions.