Walker repro. cylinder issues

[knirirr]

I've got a Walker reproduction which appears to be an Armi San Marco model made in 1971. The cylinder has a bit of play back and forth, which could presumably be fixed with a shim, but there's another problem as well: The chamber mouths appear to be worn such that they have become slightly conical; for example, a .451 ball will go in some with very little shaving of lead and will then get stuck before it can be rammed down fully. My tools are probably inaccurate but I would guess that there's a difference of 0.1-0.2 mm between the mouths of some of the cylinders. One shot out of six is usually 6-8" or more off target as well.

Does this sort of thing seem fixable, perhaps by boring out the chambers a little (not a job I could do myself)? I wonder whether it is worth attempting to get it dealt with or whether I should perhaps replace it with something such as an Uberti Dragoon.

 

[Curator]

Before going too far with your Armi San Marco Walker, slug the bore. I have worked on several of these and have one myself (Dixie Gun Works, 1974) Most ASM Walkers have large bores (.460-.462+") and small chambers (.447-449") Why there were made this way is anybody's guess as is their rifling twist rate of 1 turn in 60". The "fix" is to bore the chambers .001 to .002 over groove diameter of the barrel then use balls that are .002-.005" larger. Cylinder/barrel gap is dependant on the length of the cylinder arbor and the adjustment of the barrel wedge. A good gunsmith can make this gun right but it may not be worth the cost. Here stateside, we have Goons Gunworks, but I don't know of anyone on your side of the pond. Perhaps someone in a local black powder shooting club can recommend someone nearby to you. A Uberti Dragoon would be a step up.

 

[4v50 Gary]

Use calipers to measure the diameter of each cylinder. I'd also range the barrel to ensure that it is aligned with each cylinder.

 

[knirirr]

Thanks for your suggestions.

I did try calipers but I don't think mine are very good. At present the wedge is fairly loose and can easily be removed and replaced by hand, pushing it fully home, so perhaps a replacement may be needed to get a tighter fit. I've had a couple of suggestions of people who might be able to take a look at it, so perhaps if a quote for the work is particularly high then it might be worth looking at that Uberti.

 

[1KPerDay]

Use calipers to measure the diameter of each chamber. I'd also range the barrel to ensure that it is aligned with each chamber.

Fixed it for you.

 

[expat_alaska]

Cylinder/barrel gap is dependant on the length of the cylinder arbor and the adjustment of the barrel wedge. A good gunsmith can make this gun right but it may not be worth the cost.

You are correct to a certain point. If the B/C gap can be changed depending upon how deep the wedge is inserted, the arbor is not bottoming out in the barrel lug arbor recess. Obtain some .002" shim washers slightly smaller in diameter than the arbor recess. Insert one at a time into the recess and reassemble the barrel to the frame with no wedge and repeat. When the B/C gap gets larger than .002", remove one shim from the recess and use a very small amount of JB Weld or epoxy to adhere the shims to the bottom of the recess. When the adhesive is cured, recheck the B/C gap (.002"-.001" is optimum). Reassemble the pistol and install the wedge. The B/C gap should not change even when tapped in with a plastic mallet. If it does, the wedge is too wide front-to-back and that dimension can be reduced slightly with judicious sanding of the wedge to reduce the width slightly. Fit and fit again.

Mike (Goon) does this same thing and if you do it yourself the cost is very minimal. Pietta's arbor/recess is almost always very good but I did install a .002" shim in one of my earlier Piettas just to get the B/C gap to .001".

Have fun!

Jim

 

[knirirr]

I took this gun to a chap who has been recommended before, and who has done the following:

• Slightly enlarge the smaller chambers so they are all the same size as the largest one.
• Build up the thickness of the wedge by welding/filing.
• Same on the cylinder end of the barrel to close the gap there.

This work was cheap and seems to have improved the ease of loading (all bullets ram to the same depth); it worked reliably at the last range session.

 

[delrom418]

Here's a link to a discussion on tapered chambers in my Walker.
Since that time, I've shot a couple hundred rounds out of it and haven't had a problem with the ball creeping forward. I've been using .451 balls and 40 grains of black powder. However, I do occasionally have a problem with the loading lever dropping while shooting it.

https://www.thehighroad.org/index.php?threads/my-uberti-walker-has-tapered-chambers.773190/

 

[45 Dragoon]

First, Curator, expat, thanks for the shout out!

Knirirr, having all the chambers the same is a good step! The arbor really should bottom out in the barrel as this is what defines the barrel/cyl clearance. Otherwise, it will never be the exact same revolver since you'll be shooting it loose (compressing the wedge, upsetting material in the wedge slot in the barrel, possibly stretching the arbor in the wedge slot area . . . . ). Make sure the rear surface of the wedge is against the barrel (at the wedge slot) and not the arbor. If it is, you can't tighten the assemblies. Only the front surface of the wedge should be against the arbor. You can file the slot in the arbor (the rear of the slot, not the front) to fix this situation.

Mike

 

[knirirr]

Thanks for your further comments, chaps.
As far as I can tell the wedge is now OK after the modifications done to it.
I've been using about 35 grains of FFg which seems to be the minimum that fits comfortably, though I may increase that to 40 or 45. The loading lever rarely drops on that load.

 

[expat_alaska]

I don't think you are listening to Mike (Goon) insofar as the barrel lug recess and the arbor fit. You can adjust the wedge dimensions all you want and firing the gun will still beat the heck out of the wedge if the arbor is not seated squarely into the barrel lug recess. The wedge is not designed for nor intended to adjust the barrel/cylinder gap. Its sole purpose is to hold the barrel to the arbor. That is all.

You really need to check the arbor fit to the barrel lug recess. If it is short you need to add shims into the arbor recess until it bottoms out and you have a barrel/cylinder gap of .001"-.002" and no more.

Good luck in your endeavours, sir.

Jim

 

[knirirr]

Make sure the rear surface of the wedge is against the barrel (at the wedge slot) and not the arbor. If it is, you can't tighten the assemblies. Only the front surface of the wedge should be against the arbor.

That is indeed how it appears - thanks.
I tried taking a photograph to show this but wasn't able to get a clear view of it with a phone camera.

I don't think you are listening to Mike (Goon) insofar as the barrel lug recess and the arbor fit.

As I replied above, it looks OK.