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How to determine if your cylinder is shaved

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Zeliard
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How to determine if your cylinder is shaved

#1 Post by Zeliard » Fri Jul 28, 2017 1:29 am

Originally posted by RWS.

Our own RWS wrote this up and is so clear I am making a sticky out of it.

There are 3 checks one can do when trying to determine whether or not a .455 Webley has been altered to accept .45ACP cartridges.

1. Open the action and look at the rear cylinder face. There are usually factory markings on the cylinder face of an unaltered Webley that will be missing on an altered gun. A magnifying glass is helpful here.

2. Examine the serial number on the cylinder. Usually an altered gun will have about 1/3 to 1/2 of each number eaten away at the bottom of each digit.

3. Close the action and try to insert a nickel between the cylinder and recoil shield. The maximum headspace, or gap, between the cylinder & recoil shield is a bit less than .050" in an unaltered gun and a nickel is thicker than this, so a nickel should NOT insert into an unaltered gun. Think of the nickel as a go/no-go gage.

For Webleys converted to .45 Colt caliber (far less common than .45 ACP conversions), look to see if the cylinders have been counter-bored so that part of rim will sink down into the cylinder and approximately .030" will sit up above the cylinder face. Also, .45 Colt conversions will have the cylinder throats bored forward to accept the longer .45 Colt case. Unaltered Webleys have their cylinder throats start about halfway from the rear of the cylinder. On .45 Colt conversions the throats will be bored forward 3/4 of the way (or more) from the rear of the cylinder.

Hope this is helpful.

-Bob
Proud alumni of Transylvanian Polygnostic University. "Know enough to be afraid."

"Vertroue in God en die Mauser".-Faith in God and the Mauser.

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Re: How to determine if your cylinder is shaved

#2 Post by Markeb2800 » Fri Jul 28, 2017 9:13 am

Thanks.

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Re: How to determine if your cylinder is shaved

#3 Post by indy1919a4 » Fri Jul 28, 2017 2:53 pm

Thanks for this..

But a question, even if you have a Webley that has been converted, It seems there should be no issues having it shoot .455 webley ammo.. I do understand that shooting full power 45 ACP can be an pressure issue.

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Re: How to determine if your cylinder is shaved

#4 Post by RWS » Sat Jul 29, 2017 7:04 am

Excellent question. The problem is the headspace. The rim thickness on a .455 Mk I or Mk II cartridge is approximately .030". Maximum headspace for an unconverted Webley is .050", so the .455 round in a Webley has about .020" of normal clearance or "slop".

Both .45 acp cartridges in moon clips or .45 AutoRim cartridges require a headspace of approximately .110". The rim thickness of a .45 AutoRim cartridge is approximately .090" (the same as the distance from the front of a moon clip to the rear of the case in a .45 acp round). So... as with the .455 round above you end up with about .020" of normal clearance with either .45 AutoRim or moonclipped .45 acp cartridges.

And therein lies the problem with shooting .455 Webley cartridges in a converted/shaved Webley. There is so much extra clearance or "slop" in the headspace that the firing pin will not reliably set off primers. You can still insert .455 rounds but the shaving process on the cylinder means the case has effectively been moved forward about .060".

IMHO, the best solution for converted Webleys is to load your own reduced power ammo in .45 AutoRim cases. It just makes it far less likely to accidentally stuff full bore .45 acp rounds into the gun.

- Bob

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Re: How to determine if your cylinder is shaved

#5 Post by indy1919a4 » Sat Jul 29, 2017 6:44 pm

OK, I agree with all the points you made, And if I may define "slop", you mean fact that the shells are not held in tight and if you were to point the pistol up in the are you would hear them rattle around..

Now in truth in lending here the firing pin on that Webley is very long. And I have placed several webley 445 rounds through my shaved cylinder with never a miss fire... (I did have one, but the hammer dented the Primer very nicely, and I think it was an ammo issue).

And I agree with you about loading down you 45 auto rim ammo for the Webley.. But there is still a difference in Bullet size ???

The guy who I purchased my Webley from must have fired several 100 full boat 45 acps without any issue, Not that this is good, Just a fact. His only complaint about it was that it was pretty inaccurate.. When I use the 445 webleys in it, there is no issue I have with accuracy.. Well other then user errors.. :)

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Re: How to determine if your cylinder is shaved

#6 Post by RWS » Sun Jul 30, 2017 8:14 am

Good point, Indy. I guess it would be more accurate to say that you can't necessarily expect a converted Webley to reliably set off .455 rounds. The one I had several years ago would only fire about 30% of the time with .455 ammo. I got rid of the conversion when I found a couple of nice unconverted guns.

Part of the variability comes from the conversions having been done by numerous individuals, both professional and amateur, and just how much material was removed from the rear of the cylinder. The more material removed, the less reliable the pistol is likely to fire. Then there's the question of just how strong (or weak) the mainspring is, etc, etc.

As to your comment concerning the long firing pin, I have an old Webley Mk VI armourer's manual that specs firing pin protrusion at .050." Yours might protrude more, I dunno. Easy to check though.

As far as I'm concerned, the jury is still out on the whole bullet sizing thing. I have been trying to pin this down for several years now. I have checked maybe two dozen Webley and Enfield Mk V and Mk VI .455 revolvers. The cylinder throats on ALL of them have miked out at right at .450". I haven't checked the bore diameters on more than about 10 revolvers but of the ones I've checked the smallest was .448" and the largest was .451". Add into the mix the Webley Mk VI Armourer's manual that says barrels should be drilled with a .442" drill with grooves that should be .004" deep and you come up with a .450" groove diameter (.442+.004+.004=.450). Amazingly, this is the same as all those cylinder throat and barrel diameters I've been checking. So... if all this is accurate, where does this whole .455 caliber thing come from?

Lots of knowledgeable internet people say this is because bullets for Webleys were originally hollow-based soft lead of .455" diameter. They were supposed to be squished down to .450" diameter as they passed through the cylinder throats and then the hollow base would cause the bullet to bump back up to .455" diameter. This makes no sense at all to me, particularly in light of the fact that I have yet to see either a Mk V or Mk VI barrel with a .455" groove diameter.

What does make sense to me (and is currently a belief only, not an established fact) is that the older black powder Marks I, II, & III may have required deeper grooves due to black powder fouling so they may have been produced with true .455" groove diameters and that groove depth perhaps was dialed back when smokeless powder with much less fouling came into use. Again, this is just speculation on my part. Finding those old black powder models with pristine barrels to check is tough.

Assuming my theory is correct that leaves backwards compatibility as the only logical reason I can think of for still producing .455 ammo with true .455" diameter bullets. Such ammo would work correctly in the older BP revolvers, and the .450" cylinder throats on the newer guns would ensure that the bullets got swaged down an extra .005". Of course, all this could be nonsense. It's just my pet theory at the moment.

in any event, (especially if you are using conventional/non-HB bullets) .451" lead bullets work just fine in my Webleys. And yes, I also get better accuracy with lead bullets than with jacketed bullets. I'll bet if you check your cylinder throats, Indy, that you will find them to be .450" diameter (or less) so going out of the way to find .455" diameter bullets for reloading is kinda pointless, IMHO. YMMV.

-Bob

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Re: How to determine if your cylinder is shaved

#7 Post by indy1919a4 » Mon Jul 31, 2017 2:58 am

Many thanks RWS, I guess i was spoiled by the one I got, It was always worked well and never realized that others had issues..

I did not know that the Conversions were done by many parties, I really thought that this was done by one importing company.. This even makes more
sense.. And explains even more..

And the bullets that the guy shot out of this before was just off the shelf FMJ bullets so that may explain the accuracy issues...

Again may thanks for your insights...

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