I have Mark Vis and their Enfield "Spin-offs" (yes, Enfield made Mark VIs in 0.455 after WWI for the British Army). Unfortunately of the 6 I own (combining Webley and Enfield), five are cut for 0.45 ACP, but one Webley is from the late South African commercial purchase and is still in 0.455. I load for the cut ones using 0.45 AR and 255 grain Lead Heads sized at 0.454 with fps of ~640. This mimics the 0.455 Webley load.

In addition, I have four Webley MkIVs all marked "war finish" which was Webley's way of saying that these were not up to the prewar finish standards but were 100% functional. For these, and for my Enfield No2's (No 2 MkI and then I* and I**) I use 38 SW brass and 180 grain lead FPs sized at 0.360. At 650 fps, these match the military round with the 178 FMJ bullet. Great fun to shoot and I would not like to be hit by any of the rounds irrespective of calibre. Dave_n