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Special Interests - Groups & Societies => The Barracks => Topic started by: Tascosa Joe on September 06, 2019, 08:01:20 AM

Title: British 455 MK I & II
Post by: Tascosa Joe on September 06, 2019, 08:01:20 AM
Do any of you have case dimensions of these cartridges?  My copy of "Cartridges of the World" has them listed but no dimensions.   
Title: Re: British 455 MK I & II
Post by: Baltimore Ed on September 06, 2019, 09:21:48 AM
Here you go Joe.
Title: Re: British 455 MK I & II
Post by: Sir Charles deMouton-Black on September 06, 2019, 12:22:11 PM
My copy of the 3d ed. of COTW shows both dimensions. The Mk II shows a case length of .77 in. and a slightly larger rim diameter of .535.

As most Webleys have tapered, not stepped, chambers I can get away with using a .45ACP LEE case trimmer when doing "case conversions" to the Mk I case. The difference is only .02, (.89 to .87). The PITA is the thinner rim thickness!
Title: Re: British 455 MK I & II
Post by: RattlesnakeJack on September 06, 2019, 06:35:59 PM
It is my understanding that the diagram posted by Baltimore Ed shows the SAAMI specs (maximum?) for the .455 Colt cartridge, which was effectively a North American commercial version of the Mark I Webley cartridge, although expressed dimensions do seem to vary slightly.

Here are diagrams from the British War Department's "Treatise on Ammunition", which give "high" and "low" acceptable dimensions.  The Mark I diagram is from the 1902 edition of the Treatise, the Mark II diagram is from the 1905 edition -

(https://imagizer.imageshack.com/v2/1168x700q90/924/vHlTR1.jpg)

       

(https://imagizer.imageshack.com/v2/758x368q90/924/JkcKiy.jpg)

For comparison, here is a composite of digrams from Dowell's "The Webley Story", for the Mark I and II bullets and the cartidge case used for the Mark I cartridge and the shortened version used in the Mark II cartridge (and subsequent cartidge versions) -

(https://imagizer.imageshack.com/v2/1057x450q90/924/1SsY2y.jpg)
Title: Re: British 455 MK I & II
Post by: Tascosa Joe on September 06, 2019, 10:37:35 PM
Thanks to all.