.455 Eley Colt New Service Chamber Dimensions

[Throwback]

Hi guys, Just got a NS in .455. Not shaved or countersunk. The chambers accept loaded .45 Colt but the cylinder will not close because the rims are too thin. I chucked up 20 Schofield cases and turned the rims down. I would like to load using the Schofield cases. I prefer them to the longer .45 Colt cases for loads on the lighter spectrum and it avoids potential of my putting powerful .45 Colt loads for my Ruger in weaker revolvers.

Question 1: Have my chambers been altered? (Were the throats once different for the much shorter Eley cartridge?)

Question 2: Have others loaded Schofield or .45 Colt cases with appropriate (lighter) loads for use in .45 Eley revolvers?

Chamber throats appear to be .454 (measured by pushing slugs through) and I suspect that the groove diameter is slightly smaller than that. Haven't bothered to slug it.

[Outpost75]

In my 1914 date of manufacture Webley MkVI I load the Accurate 45-262H bullet

207218

with 3.5 grains of Bullseye in MODIFIED Starline .45 Schofield cases which have had the rims turned and thinned from the front to 0.040" and case length trimmed to 0.87". In a tight and sound New Service you could cautiously increase the charge to 4 grains of Bullseye or 5 grains of Unique or Universal, but I do not recommend going above 3.5 grains of Bullseye in the top-break Webleys.

Your cylinder throat dimensions sound normal for a Colt and are the same as my Colt NS M1909 in .45 Colt. Original .455 Webley revolvers typically have tight cylinder throats of .450-.451, despite having larger groove diameter. Shooting oversized bullets in the tight throats causes a steep rise in pressure.

My MkVI had throats of widely varying diameters from .449-.452 among the different chambers of the same cylinder, which were also pitted from use of wartime corrosive ammo. I had DougGuy hone and uniform the throats to .4555 and the revolver shoots MUCH better now, all six chambers now being of uniform dimensions with almost all of the pitting now gone.

You can buy Starline .45 Schofield cases already modified to .455 Colt/Eley from Ron Reed at Reed's Custom Ammo:

http://shop.reedsammo.com/455-Eley-455-Colt-Brass-455eleybrass.htm

Pressure tested .455 load data here:

https://castbulletassoc.org/forum/thread/ed-harris-cast-45-cal-cast-bullets-455-webley/?order=all#comment-98e46a36-2d3a-460f-9f14-a72001802b11

[Throwback]

My MKVI is a totally different animal and has a much shorter cylinder and throat. I don't want to shorten my brass at all. In a sense what I seem to have is a .45 Colt/Schofield with thin rims. I will be perfectly tickled with that as I can use Schofield data. I ran the RCBS 45-270SAA over 5 gr Titegroup and am very pleased with the accuracy. 1 handed 10 yards 2 inches. My Webley does not do as well.