Should I read the throats in my .455 Webley?

[samwithacolt]

I have a mk 1 Webley, shaved to .45acp. The cylinder throats measure .448/.449".
4 gr of unique under a 250 gr soft .452 bullet is starting to keyhole. 4 1/2 gr shoots a little better, but I don't want to push this old girl too hard. The rifling is good. I haven't slugged it yet, but I can't get a .452 bullet into the muzzle or past the forcing cone.
I got a 29/64 reamer today, but it measures almost .454". Is that too much? I don't want to spend the money on Brownells, I had hoped to get away with this chucking reamer I ordered online.
Thoughts?

[DougGuy]

You do NOT want that chucking reamer ANYWHERE NEAR that cylinder!

For that one I would definitely suggest slugging the barrel with a dead soft lead ball, then miking the ball with a micrometer, not a caliper.

I have done a few of those at .455" because the groove diameter is closer to .454" than .451" so you definitely want your boolit bigger than the groove by .001" minimum.

For the reamer, you will be best served with live pilots, since the solid nose reamer pilot is .447" or some ridiculously small dimension, it might as well not have a nose on it at all if it doesn't fit snugly in the throat. THE PILOT is the only thing that holds the reamer concentric to the existing throat, and is the exact reason you do not want to attempt this with a chucking reamer. You have absolutely ZERO control over how concentric the new throat will be.

Get the barrel slugged before you order a reamer so you know what size reamer you need, might have to call Dave Manson and get your reamer if you need a .4545" or .455" since Brownell's likely doesn't stock those odd sizes. Manson makes the reamers that Brownell's sells. Get the pilots that will fit very snugly into your existing throats, you may need more than one, I have used as many as 4 on the same Ruger cylinder, you may need 2 maybe 3 on your Webley but you want them tight in each throat. THAT is the trick of having the throats stay on center, there is no shortcut here that works, the fit of the pilot is critical.

[blpenn66502]

Think the various Mk Webleys are usually marked .450/.455 on the barrel and the throats are small .450ish but the bore runs .455ish. Brits seem to love the hollow base bullets and the throat/bore difference was one on the reasons the standard webley bullet in use was a hollow base. A throat closer to the bore would help I'm pretty sure. There was a .450 round the British used that pre-dates the .455 Webley. IIRC the reason for the dual marking.

[Outpost75]

Doug did my Webley MkVI, original throats were undersized and pitted. Now uniform .455, most of pitting cleaned up and accuracy much better.

226294226295226296

Here is my Accurate Molds design for the .455, use 3.5 grains of Bullseye for 550 fps.

226297

[Clark]

I have a Colt 1917 455 Eley made in 1920 that someone reamed out and remarked to 45 Colt
I have a Colt New Service 455 Eley made in 1916 that is still original.
I completely forgot about them.
I see I made a video on how to turn 45 Colt brass into 455 Eley brass.
https://www.youtube.com/watch?v=c9bQkVU073Q
That is a waste of time now
https://www.starlinebrass.com/brass-cases/455-Webley-MKII/

https://loaddata.com/images/database/ACFD9A.gif

[Bigslug]

Being shaved for ACP, the cylinder is already "done" as far as historical correctness, so unless you plan on ordering a hollow base MKII or MKIV mold from MP Molds, reaming out is probably your best bet. This kind of job is what DougGuy DOES, so you might just save yourself the grief and sic him on the problem.

[DougGuy]

The problem, is that he is in Alberta..

[Bigslug]

Unless there's something ELSE insidious that the minions of repression have come up with, there's nothing to stop one from shipping "steel tool parts"

[DougGuy]

He may be able to ship it in, but a US citizen cannot ship gun parts out of the US without a very expensive export license.