My latest acquisition: Webley Mk IV


March 17, 2013, 05:41 AM
I have a question. At some time in the past, someone punched out the last "5" in the ".455" caliber marking, aparently wanting to indicatge that the gun had been converted to .45. However, the barrel also says, "760"" (760 inches?) and "6 tons." Are these pressure ratings? Is the Mk IV REALLY OK to shoot .45 ACP?

Your thoughts?

- - - Yoda

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highlander 5
March 17, 2013, 07:55 AM
I seem to remember someone on this site or another asking the same question and got the impression that standard 45 acp ammo is hot compares to 455 Webley ammo.
I beleive 455 ammo is around 650-700 fps with a 265 gr lead bullet. You might be able to make usable ammo from 45 auto rim brass.

March 17, 2013, 09:18 AM

The 6 TONS mark indicates standard service pressure (in long tons or 2,240 lbs.), for that cartridge; it is not a proof mark. That would make operating pressure to be around 13,340 psi. The .45ACP is rated at between 19,000 to 21,000 psi. That would put the .45ACP well beyond the pressure range of even the proof loads for the .455 Webley. The .760 marking indicates the nominal length of the .455 cartridge.

March 17, 2013, 09:51 AM
Since I made the original post, I've done my homework. I guess I won't be loading this veteran with .45 ACP. I'm wondering, though, if it could still be fed .455? Might be more expensive to shoot, but at least it won't blow up on me!

- - - Yoda

March 17, 2013, 10:12 AM
Thanks, bannockburn. It's good, competent advice and information, as exemplified by your response, that makes this forum so valuable. You may have just saved me from a kaboom, because I was thinking of taking the Webley to the range today, but since reading your note, I may check to see if I can still shoot regular .455 in it.

Thanks again.

- - - Yoda

March 17, 2013, 10:24 AM
Probably not, as the rear of the cylinder will have been cut for moon clips if it has been converted to .45acp.
The best solution is to hand load .45acp to .455 pressure levels.
Use of .45ACP can result in stretching or failure of the stirrup that holds the frame together, or in extreme cases can shatter the cylinder.

March 17, 2013, 10:46 AM
I have one of these and after testing it with a number of handloads, I am going to stick with the lightest one.

Whoever did the caliber conversion did it cheap and reamed the chamber mouths oversize.

Also the barrel is not exactly small. I found .454 diameter bullets shot OK with a little leading. Smaller bullets gave more leading. I don’t have a mold that casts bullets .457, the larger dimensions are probably more appropriate.

I thought I would use some loads I developed in my 45 ACP revolvers. I had some Elmer Keith loads of a 250 with 6.5 grains Unique. That load was way to hot in a Webley. Actually stretched the top strap recess!

After that happened I realized that this mechanism is a lot weaker than any solid frame I have ever handled.

I also reconsidered using Elmer Keith loads in any of my 1917’s. His loads are entirely too hot for vintage pistols.

I eventually decided that 3.5 grains Bullseye was a good load. It shot to point of aim and was easy on the pistol.

45 Auto Rim

455 Webley MkVI rechambered 45ACP
manufactured Enfield 1923

255 LSWC (.454) 3.5 grs Bullseye thrown, R-P AR cases, CCI300 primers
Jun-Aug 02
Ave Vel = 541
Std Dev = 10
ES = 42.44
Low = 522
High = 565
N = 24
Shot to point of aim 25.0 yards

255 LSWC (.454) 4.0 grs Bullseye thrown, R-P AR cases, CCI300 primers
20-Jan-02 T = 42 °F
Ave Vel = 640
Std Dev = 21
ES = 79.1
Low = 586
High = 665
N = 12
Shot to point of aim 25.0 yards

255 LSWC (.454) 4.5 grs Bullseye thrown, R-P Auto Rim cases, CCI300 primers
20-Jan-02 T = 42 °F
Ave Vel = 681
Std Dev = 8
ES = 28.4
Low = 667
High = 696
N = 12
Shot to point of aim 25.0 yards better accuracy

250 LRN (.454) 6.5 grs Unique thrown, R-P Auto Rim cases, CCI300 primers
20-Jan-02 T = 44 °F
Ave Vel = 801
Std Dev = 21
ES = 79.2
Low = 776
High = 855
N = 12
2 O'C hold kept them all on target, medium recoil

Dangerous overpressure load. Way too hot, excessive effort to open latch, topstrap stretched!

March 17, 2013, 10:51 AM

Glad to be of service. Given the higher pressures of the .45ACP and the inherent structural weakness of the top-break design, you will have to stick to loads that are in the pressure range of the .455 cartridge. The problem is, as Radagast pointed out, is that the back of the cylinder has been turned down (or shaved as it were), to accomodate the .45ACP cartridges with moon clips. I believe that even if you found some .455 ammo it can no longer be used in a cylinder that has been modified in this way.

I think Radagast also has a very viable solution in that the best thing for you to do is to make up some light and mild .45ACP handloads for your Webley Mk.IV, based on .455 loading data. Hope everything works out okay and let us know how it goes. Enjoy.

Edit: Just saw SlamFire1's posting. Great information there!

Carl N. Brown
March 17, 2013, 10:56 AM
My MkIV has first and second BP proofs on each chamber out side of the cylinder, both with crown and VR which I take to be Victoria Regina (Queen Victoria 1837-1901). The factory thorough repair stamp appears to be '04 which I take to be 1904 (this is an 1899 design).

Mine was cut by the importer for .45 AutoRim or .45 ACP in moonclips. At some point it recieved a parkerized -looking refinish. I reload .45 Auto Rim cases with .454" 255gr bullets intended for .45 Colt cowboy loads and either BP or light Unique loads mimicking recommendations for .455 Webley in the original MkIV timeframe.

I have fired less than 100 rounds of 45 ACP in moonclips, and do not wish to test a BP proof gun further with modern ammo. I also do .455 level reloads in .45 ACP cases and use these in moonclips; these are awfully convenient for reloading/unloading the gun. The casing fired in my AutoOrdnance .45ACP pistol and carbine are actual a good fit for the .455 and I treat them as one use. .455 chambers are roomy compared to .45ACP. .45 AutoRim fired in a .455 chamber is a pain to resize.

The MkV Webley revolver is simply the MkIV beefed up for cordite and nitrocellulose powders and the outside of the cylinder is noticeably thicker. So no factory .45 ACP in my MkIV unless its the zombie apocalypse and I have no time for reloading.

March 17, 2013, 04:33 PM
These are really good write ups on the Webley.

March 17, 2013, 05:32 PM
That is a fine looking Webley Yoda. There is just something about those revolvers.

If you enjoyed reading about "My latest acquisition: Webley Mk IV" here in archive, you'll LOVE our community. Come join today for the full version!