I believe that action is a military small ring Mauser G33/40, I have seem one other rifle very similiar to the one being discussed calibre and all. The only way to confirm that is an original small ring Mauser is to measure the barrel thread diameter which should be smaller in dia. than the large ring Mauser. I believe the G33/40 is a fairly rare action - by the way nice gun and a keeper for sure. --- John S.