Shamus, I was talking about the pre-WW2 Rigby Mausers! When your rifle was made in 1956, the Mauser factory was out of business for ten years and the British gunmakers had hard times to find actions suitable for their Magnum length cartridges. I have seen two .375 rifles by Holland & Holland from the 1950s, one was built on a P14 Enfield, the other on an opened-up military K98k action. Rigby had some of their .416s then made on the rare Brevex Magnum actions, made in small numbers in France then. But most of that time were made on radically opened-up standard-length M98 actions, either ex-military or FN commercial. The most famous .416, Harry Selby's, was one of those opened-up actions. Of course all these actions used post-WW2 were not numbered in the Mauser, Oberndorf commercial way.