455 Revolver
455 Enfield, 455 RevolverMK I, 455 Colt,
455 Webley MK II, 455 Revolver MK VI
Current & Obsolete Pistol Cartridges
The .455 Revolver has many designations a/k/a .455 Revolver, .455 Webley, .455 Colt, .455 Enfield, .455 Eley, .455 Target with
many various versions;
Mark I, Mark II, Mark III, Mark IV, Mark V, Mark VI. We will explain them one at a time:
Mark I:
 Introduced around 1891 to1897 as .445 Colt ,.455 Webley, and  .445 Enfield Mark I, many purists  would say they differ in
loads and bullet  weights, but to the best of my limited knowledge they are interchangeable and will work in the same revolver.  The
bullet  is  .445"to.461" in diameter, case rim diameter is .525" -.535", case length is .850" to .886", over-all cartridge length is 1.157" to
Mark II:  This is where the Enfield and the others (Webley MK II or revolver MK II) differ:
 A. In the Enfield Mark II there was a bullet change to softer lead and bees wax lubrication, but no case length change over the Mark I.
 B. In the Webley Mark II  or revolver Mark II, they had a softer case, were tested and used from the early 1890s and reintroduced
around 1914 to the British Army. This cartridge was shorter than the Mark I due to the use of smokeless powders (Cordite)  and the
need for less powder and case volume to achieve the older black powder pressure.  Case length was reduced from .850" to .886" to .
740" -.760" and a lead bullet.
Mark III:  The Webley Mark III was basically a high pressure load wad-cutter (blunt ended bullet) of the Webley Mark II and
nicknamed "The Man Stopper”  and was discontinued round 1902 due to over powered (recoil). The Mark II and Mark III were
basically being tested  and used at the same time in history.  Cases were the same length as the Mark II but over-all cartridge length was
shorter (.966" to .968") due to the short wad-cutter lead bullet.
Mark IV:  This cartridge was adopted by the British Army in 1909. It was more powerful than the Mark II but less powerful than the
over powered (recoil) of the Mark III.  Lead Bullet.
Mark V:  This cartridge was adopted by the British Army in 1912; the only difference between the Mark IV and Mark V is the bullet
alloy - harder in the Mark V. Lead Bullet.
Mark VI:  This cartridge was adopted by the British Army and Air Force in 1939. This was the first version to use jacketed bullets
instead of the lead bullets in all the past versions. It was used in Britain until 1946.
In Summary:
The .455 Colt and .455 Enfield were only produced in the longer Mark I length: case length was .850" to .886."  The over-all cartridge
length is 1.157" to 1.448" and only loaded with black powder, although later in history.  They were loaded by commercial loaders with
smokeless powder after the pistol was available to the public and loaded to black powder pressures.
The .445 Webley a/k/a .445 revolver, was loaded in Mark II, III, IV, V and VI and loaded in black power in Mark II and smokeless
powder in Mark II, IV, V, and VI.