I've made arrangements to purchase a 455 Webley Mark VI from the estate of a recently deceased shooting buddy

. More for sentimental reasons than anything but I do plan to shoot it.
I have a reasonable selection of 45 cal cast bullets available but I concur with what bearhunter has stated. To that end, the guy I now get all my cast bullet supplies from, just happens to have a hollow base cast bullet available for the 455.
I did find some reload data for the 455 Webley, some in an old well used and very tattered copy of the 1st Edition Lyman Book of Cast Bullets. I also found some somewhat similar data in P.O.Ackleys Volume I Handbook For Shooters & Reloaders. Hope this is of some help and the Lyman data is as follows;