I have some of the rounds in my collection and in essence it is no more nor less than a .416 Remington, but arrived at by a complicated and expensive route.

ammo is loaded for H&H by Wolfgang Romey, I think, but may be wrong on bore size being less than .416, but haven't checked my samples, so as I said I will stand correcting here.

The case has minimal shoulder due to the taper so requires the belt to headspace. It would require chamber reamers that few will have.

Peronally, i would take advantage of that large action and go for .416 rigby anyday, but that is purely my own personal opinion.

If you do go that route you will however end up with a perfectly serviceable cartridge, kind of like re-inventing the .416 Taylor or .416 Remington