.455 Webley Loads Using 45 AR Brass

[Scott.M]

The Mk I was fielded in 1890/91 as a black powder cartridge. The Brits changed from black powder to Cordite in the mid- to late 1890's. There was a transition period between MkI and MkII cartridges where Cordite was introduced, still in the Mk I cartridge. This was around the time of introduction of the Webley .455 Mark II Pistol. The interesting thing there (at least for me) is that the briefly produced MkI (Cordite) kind of shows up again in the modern Canadian Dominion Colt/Webley MkI/II cartridge, of which the brass case is +/- the same length as the original MkI, and happily, the 45AR.

Nice, but this thread began as you asking about the MkVI. No need or worry about smokeless conversion for the MkVI.

[Colony]

Nice, but this thread began as you asking about the MkVI. No need or worry about smokeless conversion for the MkVI.

Agreed, no worries. The MkVI was proofed for smokeless.

[Colony]

In the .45 AR brass you could increase the load safely to 4 grains, but I consider 3.5 as the starting load and 4 grains as max.

Do not exceed 3.5 grains in the shorter MkII cases for the Webley top breaks.

Of all the powders that are not available right now (Bullseye and Unique among them), Winchester 231 seems to be an exception. Any experience with 231 in 45AR for the Webley...and other suitable powders/loads?

[Outpost75]

Of all the powders that are not available right now (Bullseye and Unique among them), Winchester 231 seems to be an exception. Any experience with 231 in 45AR for the Webley...and other suitable powders/loads?

Lyman Cast Bullet Handbook, 4th Edition (2010)

p279 shows 231 in the .45 Auto Rim with #452374 225-grain LRN No. 2 alloy at OAL 1.265":

start 4.0 grains 231 for 660 fps @ 6,900 cup, max. 5.5 grains 873 fps @ 13,800 cup
(I would not exceed 5 grains in the Webley)

I would not be worried about trying the 4 grain charge with a heavier lead bullet up to 265 grains.

Any pressure-tested .45 Auto Rim or .45 ACP data you come across from a current, reliable industry source, which is below 13,000 cup is fine in your Webley.