Read your post and hoped it was the answer I was looking for. When I got home I checked it against some .405 Win. The rim is too thick and the base is 0.458" when I need 0.478". It might expand but then it might split. I think I'll save my 405s for my 1895 Winchester. A gun that is too much fun to shoot for it's own good. I have several options as to cases to use. Now to find the time to do it.