The 47mm case shortened from 11.15x60R is a good possibility but if it is marked 10,5 the nominal caliber would likely be 10.75x47R. This was a popular case in lengths from 43mm to over 60mm. Beside the MB case other possibilities are the M88/ Lancaster case, 450 and 500 base British cases, or Colath/similar cases; but in my opinion the 360 base case is too small to consider. This is why a chamber cast and bore slug is necessary to ID the caliber.
Last edited by Der Ami; 12/12/22 09:22 AM.