I am thinking of building a .404 Jeffery on a M98 and would use Sunny-Hill's drop box bottom metal if I do proceed with a .404 Jeffery.
Andy at Sunny-Hill said the sides of the box has enough metal to widen it for the correct geometry for the .404.
Will use a copy of a H&H stock with an 8.5" tapered forearm. I'm hoping it will be able to hold 4 down. Not sure I want to do it if it can only hold 3 down.