Raimey, question, if the chambers on that gun are 18.7mm=.7362 inches, would you have to have the chambers opened because todays brass,zinc, head is measuring between .738-.742, resized and could be .740-.744 un-sized. I would imagine that earlier European shell heads were smaller.

On the one I was looking at converting 19.0mm is .7480 and that is larger than L.C. Smith chambers at .745.

David