VonGruff,
My understanding is also that Selby's rifle was a standard M98 opened up. Imagine trying to get that one past the legal watch-dogs these days.
That's perhaps a nice advantage to the old DGR chamberings, large case volumes kept pressures low when Cordite was the powder of choice. I recently had the pleasure to shoot a 13-14lb 577NE built in Australia on a Ruger No1 action. Large case volume keeps pressures low and its 750gr at 2000fps was easily handled. These days we tend to load much hotter, and I doubt you'd find a 'smith willing to chamber a 416Rigby into an opened M98, knowing what may occur later when someone decides to reach for its 'ballistic potential' with a hot load.
Cheers...
Con
