I think people misunderstand the market. As long as Rigby exists and they are willing to chamber this cartridge, it will exist. It doesn't need a hundred rifles a year being chambered in it to be a success. As the value and price of the rifles will always be a custom proposition.

The cartridge is an effective for purpose choice. So that is not a question.

The only question will be how widespread it becomes if off the shelf and other makers choose or not to take it up. For example I would love one. But could never afford the London Best Rising Bite price. Conceivably a Verney-Carron, Heym or other similar brand might be achievable. Same for many other potential users.

Ammunition must already be available for it, at a price and order. Many of us ONLY reload. Ammunition makers will follow success.

The .416 No.2 Rigby has the name to draw upon.

Unlike Holland & Holland and the .400 H&H Magnum, H&H makes only a handfull of rifles each year, Rigby is making a relative lot at the prices they charge.

Krieghof's .500/416 NE was disappointing even though a few other makers chambered for it. Probably ballistically the same as the no.2. I think the Rigby name will make the difference.

Yep, the big bore market is small. Premium makers do not always depend on large numbers.