Is a .455 Webley/Eley cylinder conversion possible for a Model P Uberti?

[Virginia Gentleman]

I am curious if a .455 Webley/Eley cylinder could be fitted to a Uberti Model P SAA that is chambered in .45 Colt?  Any ideas?

[Sir Charles deMouton-Black]

The cheapest option, always my preference, is to use wildcat .455 rounds based on a case with the .45 Colt or Schofield rim.

Oh! Right! That is a .45 Cowboy Special!!!!!!

Seriously; Your idea would require a new cylinder to match the thinner rim of the .455 Colt/Eley/Webley. (Most of us .455 Webley shooters spend too much time or money acquiring cases as it is.)

[Pettifogger]

Anything is possible if enought money is applied to the project.  The question is why on earth would anyone want one?  Brass and loaded ammo is scarce.

[Virginia Gentleman]

I am well aware of .45 Cowboy, but I have over 3000 .455 Mark II cases and from a "blast from the past" this would re-create the 1873 SAA from the London office that was chambered in .455.  That being said, other than saying it is possible with money, how about some technical guidance as to what would be needed to accomplish this?

[Professor Marvel]

I am well aware of .45 Cowboy, but I have over 3000 .455 Mark II cases and from a "blast from the past" this would re-create the 1873 SAA from the London office that was chambered in .455.  That being said, other than saying it is possible with money, how about some technical guidance as to what would be needed to accomplish this?

My Good VG

Basically all you need to do is modify and fit a cylinder.

Look here
http://forums.gunboards.com/showthread.php?178541-Colt-new-service-455-eley-45-long-colt
and here
http://www.cascity.com/forumhall/index.php?topic=39491.0
and here
http://britishmilitariaforums.yuku.com/topic/10256/In-bad-need-of-help-with-a-Webley-MK-IV-455450

note especially the lovely images with case dimensions.

The dimensions suggest that for this to work you will want to start with a .45 ACP or .45 AutoRim cylinder and
have it gently reamed to accept the .455 Webley. As long as you are going to that effort, you may want to add
.455  Eley and "faux" London Office markings to the barrel, carefully worded to avoid accusations of faking or forgery :-)

for example instead of "Depot 14 Pall Mall" you could engrave "Depot 41 Pell Mell" .

just my 2 bits
yhs
pm

[Pettifogger]

The rims on the .455 are only .039 thick.  The rim on the .45 Colt and many other American cartridges have a more or less standard .060" thick rim.  On some calibers you can take a smaller cylinder, like a .357, and bore it up to the larger size.  This won't won't work with the Webley bacause with the thin rim you would wind up with excessive headspace.  The only way to do the job properly is to have a new cylinder made and filtted.

[pony express]

I have read SOMEWHER of a gunsmith whor "restores" Webleys that have been "shaved" for .45 Auto with moon clips, by silver soldering a shim to the back ends of the cylinder, so the cases would headspace Probably the same treatment would work for a Colt type cylinder.

[Coffinmaker]

Throw Money at It!!  Yep!!  It'll cost, but there are solutions.  First solution as noted above, is to a add a shim to breach face of "a" cylinder to correct the head space.  Since the 455 is a balloon head case, I'd not suggest trying to fire it with .030 or so excess head space.  Bad Ju Ju there. 
Next solution is to take .030 off the star and shim out the base pin bushing.  Now your going to have .030 excess barrel/cylinder gap.  Workable, but not optimum.
Any US Cylinder for SAA, or import for a reproduction is going to have head space for the SAAMI standard rim thickness.  Problematic.
I would personally opt for the option of adding a "shim" to the rear face of a .45 Colt cylinder.  In all probability, will machined, the shim
need not be permanently affixed to the cylinder.  The cartridge case will hold it in place.  Only a small amount of the case would be unsupported and with low chamber pressure (BP Only) blow out should not be a problem.
There is an outfit that makes a 45 ACP Moon Clip modification for the S&W Schofield Reproduction (TK something) who should be well equipped to make you a shim plate.

Coffinmaker

[Virginia Gentleman]

It seems to me atleast that the best solution would to be to add a shim to a .45 ACP cylinder, have it silver soldered on, then have the chambers re-cut for .455 Eley/Webley Mark I.  This way both Mark I and Mark II cartridges will chamber.  Thanks for the input guys!