This is the .416 Rigby is offering presently.

http://www.johnrigbyandco.com/the-big-game.html

They are using only the Golmatic German action stamped Mauser 98 Magnum on the left wall. Mauser does not manufacture actions. There are three different flooplate depths depending on cartridge (up to .505 Gibbs).

http://www.mauser.com/en/products/m98/m98magnum/

This is the same action used by Prechtl.

http://prechtl-waffen.de/Prechtl/en/Rifl...8_magnum_action