Webley Mk VI Chamber Issues

MoscowMike · August 13, 2015, 10:00 PM

I have a Webley Mk VI top-break revolver, 1916 vintage, which was shaved to shoot .45 ACP. When I got it the hand was chipped and it wouldn't reliably rotate the cylinder into a tight lockup. Couldn't find a replacement hand, but a local gunsmith tig welded the end, fought with it and finally got it locking up tightly. He then put together some very light handloads behind .452 lead bullets and tried it out - no problem but not very accurate.

I know you need to keep to low pressure, so I built some medium loads, 4.9 gr Unique in .45 AR cases behind a 265 gr LRNHB bullet. With those hollow-base bullet I got pretty good accuracy, 2.5" at 15 yd single-action off the bench. Ran about 6" high. Two of the chambers were tough to extract. The cases came about half-way out easily, but stuck and I had to work to remove them. The other four were no problem

A machinist friend of mine checked the chambers on the Webley. The four which didn't have problems were about .484 from the mouth of the case on towards the forcing cone. The two that had extraction problems were also .484 at the mouth, but opened up to .487 and then back down towards the forcing cone, as if the cylinder ballooned a bit.

The gunsmith said the cases he used (.45 ACP in half-moon clips) came out easily but were sooty on the outside. Light loads behind smaller diameter bullets hadn't really expanded.

The cylinder walls look really smooth, no machining marks. Hard to say what would have caused the interior expansion. I assume that if it had been fed a steady diet of hi-pressure 45 ACP loads it might have stretched things a bit, but just two chambers, and just 3 thousandths? Could have been careless machining, I suppose. I could try to polish the mouths on those two chambers, but I'm thinking taking them out to .487 would be asking for trouble.

So - unless .487 is safe, or there's another solution it looks like I'm looking for a replacement cylinder. Any suggestions?

Dixie Gunsmithing · August 14, 2015, 01:25 PM

I don't know if that would be safe. However, it is either that, or try to find a cylinder. I cant say it is safe, since those two bores have been over-pressurized already, to the point of plastic deformation, (the bores have had their maximum yield strength exceeded, which does weaken them).

It would be nice to see an original print, and see what the cylinders bore tolerance was, and maybe the specs on the pressure ratings. Finding a print, is probably impossible.

Slamfire · August 14, 2015, 03:24 PM

Quote:

The cylinder walls look really smooth, no machining marks. Hard to say what would have caused the interior expansion. I assume that if it had been fed a steady diet of hi-pressure 45 ACP loads it might have stretched things a bit, but just two chambers, and just 3 thousandths? Could have been careless machining, I suppose. I could try to polish the mouths on those two chambers, but I'm thinking taking them out to .487 would be asking for trouble.

I have one of those 50's conversions and the workmanship is deplorable. Sloppy chambering and no thought as to end user accuracy.

I have heard others say it, and I believe, standard 45 ACP loads are above the proof loads for these Webleys. Cylinder expansion might be due to that. If your cylinder has expanded due to over pressure loads the revolver is not safe to shoot. Once a material exceeds yield, the cycles to failure are extremely short, and quite often, it takes less strain to induce more yield.

MoscowMike · August 14, 2015, 04:03 PM

Thanks for the info. I believe working pressure for the Webley .455 is 13,000 psi, where the .45 ACP is 19,000. Many Webleys converted to .45 have stood up to the higher pressure but it isn't safe so this one may well have stretched out.

According to Wikipedia

the .455 base diameter is .480, where the .45 acp is .476, so the cartridge is already small for the chamber on the shaved cylinders. And the chamber walls are thin so I don't have any faith in the idea of drilling and sleeving.

Sounds like a replacement cylinder is the way to go, but they are hard to find. Numrich, Apex and Northridge show no stock. Any suggestions?

I thought I was getting into a Webley for a reasonable price, $450, but - I guess not!

**4V50 Gary** · August 15, 2015, 09:58 AM

Please reread DixieGunsmithing's post.

August 13, 2015, 10:00 PM	#1
MoscowMike Member Join Date: November 14, 2008 Posts: 57	Webley Mk VI Chamber Issues I have a Webley Mk VI top-break revolver, 1916 vintage, which was shaved to shoot .45 ACP. When I got it the hand was chipped and it wouldn't reliably rotate the cylinder into a tight lockup. Couldn't find a replacement hand, but a local gunsmith tig welded the end, fought with it and finally got it locking up tightly. He then put together some very light handloads behind .452 lead bullets and tried it out - no problem but not very accurate. I know you need to keep to low pressure, so I built some medium loads, 4.9 gr Unique in .45 AR cases behind a 265 gr LRNHB bullet. With those hollow-base bullet I got pretty good accuracy, 2.5" at 15 yd single-action off the bench. Ran about 6" high. Two of the chambers were tough to extract. The cases came about half-way out easily, but stuck and I had to work to remove them. The other four were no problem A machinist friend of mine checked the chambers on the Webley. The four which didn't have problems were about .484 from the mouth of the case on towards the forcing cone. The two that had extraction problems were also .484 at the mouth, but opened up to .487 and then back down towards the forcing cone, as if the cylinder ballooned a bit. The gunsmith said the cases he used (.45 ACP in half-moon clips) came out easily but were sooty on the outside. Light loads behind smaller diameter bullets hadn't really expanded. The cylinder walls look really smooth, no machining marks. Hard to say what would have caused the interior expansion. I assume that if it had been fed a steady diet of hi-pressure 45 ACP loads it might have stretched things a bit, but just two chambers, and just 3 thousandths? Could have been careless machining, I suppose. I could try to polish the mouths on those two chambers, but I'm thinking taking them out to .487 would be asking for trouble. So - unless .487 is safe, or there's another solution it looks like I'm looking for a replacement cylinder. Any suggestions?

August 15, 2015, 09:58 AM	#5
4V50 Gary Staff Join Date: November 2, 1998 Location: Colorado Posts: 21,843	Please reread DixieGunsmithing's post. __________________ Vigilantibus et non dormientibus jura subveniunt. *Molon Labe!*

August 14, 2015, 01:25 PM	#2
Dixie Gunsmithing Moderator Emeritus Join Date: April 27, 2013 Location: Ohio Posts: 1,923	I don't know if that would be safe. However, it is either that, or try to find a cylinder. I cant say it is safe, since those two bores have been over-pressurized already, to the point of plastic deformation, (the bores have had their maximum yield strength exceeded, which does weaken them). It would be nice to see an original print, and see what the cylinders bore tolerance was, and maybe the specs on the pressure ratings. Finding a print, is probably impossible.

August 14, 2015, 04:03 PM	#4
MoscowMike Member Join Date: November 14, 2008 Posts: 57	Thanks for the info. I believe working pressure for the Webley .455 is 13,000 psi, where the .45 ACP is 19,000. Many Webleys converted to .45 have stood up to the higher pressure but it isn't safe so this one may well have stretched out. According to Wikipedia the .455 base diameter is .480, where the .45 acp is .476, so the cartridge is already small for the chamber on the shaved cylinders. And the chamber walls are thin so I don't have any faith in the idea of drilling and sleeving. Sounds like a replacement cylinder is the way to go, but they are hard to find. Numrich, Apex and Northridge show no stock. Any suggestions? I thought I was getting into a Webley for a reasonable price, $450, but - I guess not!