I would be curious what Holt's say about the gun . Maybe he had a WR .470 in addition to his WR .476. I "zoomed in" on one of those targets thinking it would say .476 , however it appears it says .470 ????? The picture with the buffalo is his .500 Bosswell (I think). And the lion picture is his .476 ( this gun maybe ?). Great to speculate !!
Robert

Daryl I'm very envious of you , Mr. Keith was one of my boyhood heros . Would have loved to visited with him.