Webley mark 4 -38 S&W keyhole problem

[Polymath]

Hi Guys.
I've been stewing about this for a couple days and I'm stuck.
I have a project ongoing. Loading 38 S&W in a mark 4 Webley. 4" barrel.
I have cast up some very nice looking Lee 160 gr L2 boolets (the mold throws them at .360 dia) and diluted Alox lube.
I am getting the odd boolets going sideways through the paper. I got 2 on the first string and and on the second string. The ones that go straight are within 4 to 5" spread. It is shooting 6" high at 50 ft.

The charge is 2.2 gr of W231. I checked the case for fill level and it's fine. Just a bit under the base of the bullet. No compression loads.
I belled the mouth enough for a good entry to start the boolet. I hand weighed every charge, used a normal crimp. I am using a magnum primer as I usually do in my 38 SPL. (never see that much difference in my POA on paper.)
New, full sized Starline Brass. I plunk tested every cartridge. Wiped the cartridge when done.

The load sounds and feels normal with no signs of over pressure on the primers or sticking of the the case. The revolver is a tight lock up and functions as normal. Monster double action as per usual, smooth and silky single action. There was some dirty stuff in the barrel after a few strings but normal for starting loads. Brass looked as clean as normal. No smoking the outside of the case, so there was a good seal to cylinder.

I checked for a burr on the crown, nothing, barrel looks like the day it was made. I checked the diameter of the cylinders and only 1 was about a half of 1 thou different. Might be how I measured it too, but nothing out of spec.
I slugged the barrel and it was within specs. Nice sharp lands.
This morning I rechecked the bullets and they are still .360 or within a half a thou.

When I think about keyholing, I check all these things, but if it was a rifle I would say it is a twist issue. Too heavy a bullet for twist. Which means the bullet doesn't stabilize. But these revolvers were designed for weights between 145 (factory) to 200 grs. I can't see that being the issue.

Any of you got any ideas? What is the normal POA for these guns?

[Outpost75]

Check cylinder throat diameter with gage pins. My Brit .380-200 revolvers all have .363-.364 throats. I load NOE .364-204RN bullet as cast and unsized lubed with 45-45-10 with 2 grains of Bullseye. Your 160-grain bullet will probably be 4-6" low at 25 yards. Your 231 charge is a bit light for a 160- grainer but is correct for a heavier 200-grain bullet.

[Hick]

How hard is your alloy? I have a Mark VI that has cylinder throats just a thousandth or so smaller than the bore-- but I use 1:20 alloy and they seem to obturate enough that they shoot really good. I read somewhere (can't remember where) that a soft alloy helps these pistols.

[Polymath]

Hick, Outpost75
- I may go with a softer alloy too but so far I'm just going by the book. My L2 comes in around 14.6 BHN.

The next thing I'm going to try is a faster burning powder like Bullseye to see if that cures the problem. Perhaps a faster powder will upset the boolet faster. I'm also trying a second coating of Alox.
I rechecked the cylinder and re-slugged the bore too.

I've got some BE in a few test loads at different charge levels. 2.2, 2.4, 2.6 I should know after a string of each. The snow is still too deep here to search for the lead to see what happened.
If softer lead doesn't help, I go the next step where I will Lement one cavity in the mold to make it bigger. Although it is a snug fit in the cylinder as it is. I'll know tomorrow.
Thanks for the help guys.

[Kosh75287]

The BEST answer is to find some soft-lead projectiles sized to .363 - .364" and use with an an appropriate charge of fast-burning propellant. A less perfect, but often usable answer is to use 148 gr. HBWCs and seat them to the same overall length as with the 146 gr. bullets. The hollow bases will expand to fill the bore and engage the rifling, delivering not-half-bad accuracy, usually.

[john.k]

The idea of these revolvers is a smaller throat promotes powder burning,and there is little likliehood of a bullet sticking in the barrel........as mentioned softer lead,faster powder...and finally have the cylinder throats reamed to groove dia.

[Hick]

The BEST answer is to find some soft-lead projectiles sized to .363 - .364" and use with an an appropriate charge of fast-burning propellant. A less perfect, but often usable answer is to use 148 gr. HBWCs and seat them to the same overall length as with the 146 gr. bullets. The hollow bases will expand to fill the bore and engage the rifling, delivering not-half-bad accuracy, usually.

Hollow base (Good reminder!) I forgot to mention that the original lead bullets the British used in the Webleys was hollow based!

[JoeJames]

Check cylinder throat diameter with gage pins. My Brit .380-200 revolvers all have .363-.364 throats. I load NOE .364-204RN bullet as cast and unsized lubed with 45-45-10 with 2 grains of Bullseye. Your 160-grain bullet will probably be 4-6" low at 25 yards. Your 231 charge is a bit light for a 160- grainer but is correct for a heavier 200-grain bullet.I agree. At 15 yards a 158 grain swc shot 4-6 inches low. Mine was a S&W Victory Model and it was obviously regulated for the 200 grain RN bullet. Whether a Webley or a Smith - dwell time is dwell time.

[Bigslug]

Hollow base (Good reminder!) I forgot to mention that the original lead bullets the British used in the Webleys was hollow based!

True, but only on the .455's. The .38's never got subjected to the same throat-smaller-than-groove problem. But yes, whatever fix we arrive at, I think the OP is suffering from too small a bullet diameter. IIRC, my Webley slugs get sized to .362"

A cheap thing to attempt would be to cast from a HARDER alloy to see if that bumps the diameter up any. A hollow base mold would probably do the trick, but if you're buying a new mold anyway, solid bases are a lot easier to deal with - just get one that drops large enough to be useful.

[murf205]

My 38 S&W is not a Webley but a S&W 33-1 and when I got it, I bought 2 boxed of lead rn ammo for the brass. It keyholed and leaded like I have never seen, as in 2 cylinders needed Chore Boy for the barrel. I pulld a couple and they were .357 dia. My Accurate mold drops at .360 which is .361 after powder coating and the little gun is dead nuts accurate now, That is how much the diameter means. Like Outpost said, get some pin gages and size to cyl size. BTY, that old "hollow base will obturate " is not a cure for under sized boolits, no matter what some gun writers will tell you.

[Polymath]

Follow up to OP-
Well I took some of the advice that you all gave. I honed out a cavity on my mold so it throws .360".
I changed the alloy to 20 to 1, and upped the powder charge to 2.5grs.
I stayed with W231 and it worked well. The Bullseye had bigger groupings. ???
So today I got my best target with a 2" group off sandbags at 50 ft. All the bullets shot straight and true. No leading and the bullets still fit nice in the case with no bulging and fit the chambers.

It still shoots high and to the left. But that's a project for another day. I can add a dab of JB Weld to the front blade and adjust it down to suit. About 1/16". I have done this with success on other firearms. Today I took a piece of tape to the blade to simulate a taller blade so I could get an idea of how much I need extra height on the blade.
It's not my firearm so I won't be changing anything without permission.

The guy had a ratty holster that didn't fit nor cover the trigger guard, so I found an extra one in my box and modified this one to fit his Webley.
The target shown is yesterdays, todays was better.
Thanks to all of you for your input.
311893311894311895

[murf205]

Pretty darn good for a Webley and might just be the snazziest stocks I've seen on a Webley too.