500Nitro. That's a very good question. I would assume that with the exclusive agreement that Rigby had on magnum Mausers ending in 1911, couple with a new long cartridge, they may have felt it necessary? Perhaps they went with the magnum for the new cartridge as it didn't require extensive modification?

Not sure as I don't have any information with me. I'm not sure if any records of Hollands that I have seen distinguish between standard and magnum length actions by serial number. It would be interesting to ask them.

I will write to them and get their records of the rifle and ask the question re standard versus magnum length builds.

Cheers, Chris