To my eyes the 404J requires a magnum length action to get the best out of it. Rigby case length is 2.90inch, the 404 is 2.87inch. Yes the 404 can and is shoehorned into opened standard length Mausers but you restrict the performance doing this.

I was tossing up between a 416Rigby and 404J. The CZ550 in Rigby was $1600 and the 404 was a couple of thou more.