If you have access to John Donnellys book have a look at
450/400
475 nitro express
476 Westley richards
50/140 ( 3 1/4") sharps
I,m not saying they are going to drop straight in but they are the closest ones I can see.
the book is called
The Handloaders Manual of Cartridge Conversions
by John J Donnelly
printed by Stoeger Publishing Co
ISBN 0-88317-136-8
good shooting
sbs470