Barrel throat leading on Smoke Wagon

[will52100]

I love this revolver, but am getting a good bit of leading on the barrel throat.  This happens with any lead bullet or lube combination I use.  It's a bit aggravating to clean out too, it's only in the first 1/2" or less, starting at the end of the forcing cone.  Best I can tell the frame is squeezing the barrel down just a bit there.

I haven't tried fire lapping yet, would this help alleviate the problem?

Other than this issue the gun is accurate and functions like a dream.  So far it's the only revolver I've got that does this.

Thoughts?

[August]

The Brownell's 11 degree reamer is your huckleberry.

http://www.brownells.com/gunsmith-tools-supplies/handgun-tools/barrel-tools/chamfering-tools/11-chamfer-cutter-prod26151.aspx

[will52100]

I've got one of those, I've used it on most of my cap guns, haven't tried it on the smoke wagon yet.

What is getting me is it isn't the forcing cone that's leading, the lead is in the groves at the start of the rifling, not in the forcing cone.  Would doing the forcing cone make a difference there?

Thanks

[Advertising]

[Fox Creek Kid]

Immediately in front of the forcing cone. If the leading is observed immediately in front of the forcing cone, then it's almost always due to a constriction in the barrel caused by an overly tight barrel/frame thread. This is most readily diagnosed by slugging the bore, and feeling for added resistance as the slug passes through this portion of the bore. Fire-lapping will usually clean this up pretty quickly and effectively. Hand-lapping requires more knowledge and experience, but allows the shooter to feel when the job is done and results in a more uniform bore surface throughout the length of the barrel.

http://www.lasc.us/Fryxell_Book_Chapter_7_Leading.htm

[Gabriel Law]

Neat reamer!

[will52100]

So I should give fire lapping a try then.

[Fox Creek Kid]

So I should give fire lapping a try then.

You should first check for constriction. As well, hard bullets & light 'gamer' loads will lead if the bullets are undersized.

[Sagebrush Burns]

Just a thought here, based on personal experience with the same problem.  Have you tried softer bullets?  Most commercial cast bullets are on the hard side which is a big contributor to your problem.  Have you tried soft lube?  Alox type lubes helped me.  Have you tried flat based bullets?  Bevel base bullets can be a contributing factor to your problem.  When I addressed those three issues, my leading problems in the throat/forcing cone area disappeared.

[will52100]

My standard black powder load is a .454 big lube bullet with pearl lube 2, or my own SPG formula.  Smokeless rounds get a .453 bullet lubed with two coats of alox/JPW/mineral spirits, 45-45-10.  Or my own mix of vaseline/paraffin/STP.  The smokeless as cast are between .453 and .454.  I size and lube with .454 size dies, or with the 45-45-10 mix as cast.  Big lube bullets get sized and lubed at .454.  Alloy for both is 20-1 lead/tin.

Standard black powder load is 38 grains of 3F Graf's, on occasion I use 2F Swiss for a little extra "oomph"

Smokeless load is 5.7 grains of Titegroup.

All bullets are flat base, 250 grainer's, tight crimp.

I get leading just past the forcing cone for about a 1/4" or so then it disappears.  This happens with all loads.  I haven't tried any jacked with this gun.

I was thinking of making about 8-10 abrasive rounds up, load and fire one at a time, cleaning between rounds.  Then 5-6 of medium grit, then fine grit.  Not sure how low on velocity I can go though, I've only got Titegroup, Unique, and black powder for pistol powders.  I do have a mould for a 200 grain big lube bullet, but haven't used it in years.

[Coffinmaker]

Your first stop is to slug the bore.  From the muzzle end.  With the bore lightly oiled, once the bullet is started through, your checking to see if the bore gets tight where it passes through the frame.  The other reason to slug the bore is to see if you are simply shooting the wrong size bullet for that particular gun. 
You may already know this, but optimum bullet diameter is between 1.2 and 1 full thou over groove diameter.  If, in this particular gun, your casting a bullet well oversize, you leading could well be because the barrel is swaging the bullet down to size.  Between all the
replies on this thread, you have a pretty good road map to resolve the problem.

Coffinmaker

[will52100]

You've got a point on slugging the bore, I assumed it's a standard .452, but I should check it.  I've never had an issue like this with a revolver before, even shooting .454 through a .451 barrel.  I'll also check the chamber throats while I'm at it.  I probably would already do that, just haven't had time to get to it.

[Sir Charles deMouton-Black]

Will; As someone suggested above, mike the barrel where it's screwed into the frame and compare with the rest of the barrel.

Heh! How could I do that? 

With inside calipers

[Fox Creek Kid]

Will; As someone suggested above, mike the barrel where it's screwed into the frame and compare with the rest of the barrel.

Heh! How could I do that? 

With inside calipers

Inside calipers are not accurate enough. All calipers measurements are + or - a few mil at best.

[Sir Charles deMouton-Black]

I understand that. If I drive a soft lead slug through a SAA barrel I have to drive it right through the frame area. Thus the slug will show the size of the barrel at the frame, where it MIGHT have been choked a bit when the barrel was screwed in.

How can I get a slug dimension in the front, possibly undeformed, part of the barrel to compare withe the forcing cone area where it might have been deformed

[Fox Creek Kid]

Two ways:

1.  one you can go by 'feel', which is of course subjective

2.  you can fill the barrel with wadding just in front of where the barrel meets the frame. Then, pour hot lead into the forcing cone area as if making a lead lap (in reverse). Let it cool & then measure that and then compare the measurement against slugging the muzzle end.

[Coffinmaker]

'Nother method.  First part - Drive a bullet into the muzzle area, maybe an inch.  Cut dowels the same size as the window and drop em in
'till one sticks out into the window, then drive the whole stack of dowels and the bullet out > measure it.
Drive a bullet all the way thru > measure it.
Then, drive a bullet in from the breach, just to the frame area, drive it back out > measure it.

It's a pain.  It will however, answer the question.  I still prefer running the slug all the way thru and "feel" for it to stick.

Coffinmaker

[Pettifogger]

'Nother method.  First part - Drive a bullet into the muzzle area, maybe an inch.  Cut dowels the same size as the window and drop em in
'till one sticks out into the window, then drive the whole stack of dowels and the bullet out > measure it.
Drive a bullet all the way thru > measure it.
Then, drive a bullet in from the breach, just to the frame area, drive it back out > measure it.

It's a pain.  It will however, answer the question.  I still prefer running the slug all the way thru and "feel" for it to stick.

Coffinmaker

+1.  Sir Charles.  The idea is that when you drive the slug all the way through the bore it will get squished to the smallest diameter.  Then when you reinsert the bullet and start pushing it through the "wide" spots will push through fairly easily.  When you hit a narrow spot you can feel the increased effort it takes to push it through that area.  We are only talking a few ten thousands of an inch in most cases.

[Fox Creek Kid]

Constriction is usually far more common on Ruger SA's IMO. However, Pettifogger & CM have seen far more Italian ones than me. I'm sure it happens on them, just that I have never seen that.

[Sir Charles deMouton-Black]

Thanks for the info Pards.

[mehavey]

Have been running a SmokeWagon 44-40 for about a year -- maybe 600-700s round through it -- and using the same load/combination as it's big brother, an Uberti`73Win (another 600-700 rounds).



 Drop the hardness to 30:1 or lower (pure lead)

At the end of a shooting session, the barrels of both guns are literally spotless/mirrors from start to finish.