I suppose F.J. used one of the super rare Jeffery rifles, less than 30 ever made. Jon Speed in his book "Mauser Original Oberndorf Sporting Rifles", pages 231 and 237, shows two such rifles, both apparently put together by the same man, though one was retailed by G.Gibbs. Both rifles are built on square bridge Mauser Magnum actions, have massive barrel shanks, same diameter as the receiver ring, and a pg stock without cheekpiece, with horn foreend tip and island type express sights.