Leading problem

[james nicholson]

I just experienced my worst leading issue in 20 years of cast bullets. My 155 gr swc Lyman, wheel weights plus 2% tin, leaded up my "new to me" 357 mag Ruger Vaquero. I have used this lead and lube combination in many 357 and 38 spec revolvers and three different rifles, without any leading issues. All of the leading, in the Vaquero, was at the breech end, first two inches, mainly at the bottom of the barrel. I only fired twelve rounds, all of which hit into a 1" group from a rest, at 50 feet. If it wasn't for the leading, it would have been excellent in this revolver. It may be my imagination, but during my three hours of cleaning the bore with Ed's Red and structured copper pads, the breech end felt slightly tighter than the muzzle end. Any and all help and advice would be greatly appreciated.

Thanks, Jim

[mdi]

Where along the barrel is the most leading?

[OptimusPanda]

I wonder what the chamber throats measure. They may be bigger than the bullets.

[gpidaho]

Bullet fit is the all important thing if you are going to eliminate leading. Ruger Vaqueros are notorious for having cylinder throats to small for the barrel. Slug your bore and use pin or plug gauges to measure the throats. Most likely you will find this to be the problem. Luckily its a pretty easy fix for a competent gunsmith. GP

[james nicholson]

First two inches, mainly at the bottom

[Bullshop]

I bet you have some choke at the frame where the barrel threads in. Try slugging once at the muzzle and pull out the slug and once all the way through. If the all the way through slug is smaller you have a problem. The tight spot will have to be lapped out.

[james nicholson]

Just slugged my cylinders again and they run .359 to .3595, all within that size. They are remarkably the same. I do not have a brass rod long enough to slug the barrel but pin gauge puts it very close to .357 at the muzzle, probably slightly over .357 when measuring a slug. my boolits are sized to .358.

[james nicholson]

Bullshop, I mentioned in my op that with a tight fitting patch on a jag, that the bore felt slightly tighter at the breach end. I thought it was my imagination. I am off to Lowe's to buy another brass rod, I cut the last one
up for various projects and now do not have a piece long enough to slug the bore.

[gpidaho]

If the throats measure as you say then I think Bullshop has the answer your looking for GP

[runfiverun]

I dunno,, a ruger with a tight spot...:lol:
probably under the frame.

[cbrick]

Just slugged my cylinders again and they run .359 to .3595, all within that size. They are remarkably the same. I do not have a brass rod long enough to slug the barrel but pin gauge puts it very close to .357 at the muzzle, probably slightly over .357 when measuring a slug. my boolits are sized to .358.

So the throats are uniform at .359-.3595, I would say Bullshop is correct. What are you sizing to? Are you using a micrometer or calipers to get these measurements?

Am I reading your post correctly? You used a pin gauge to measure the bore? That won't work, a pin gauge will tell you the bore diameter at the rifling height, what you need to know is the groove diameter.

Rick

[james nicholson]

Sizing to .358. Cylinders were each slugged and measured with micrometer. As soon as I get a new brass rod, I will slug bore. I used a pin gauge to make a guess measurement of the bore, as I said, I need a brass rod.

[Motor]

james,
It that Ruger stainless steel by any chance?

[james nicholson]

No, it is blued with case hardened colored frame. I just finished slugging the bore and Mr. Bullshop is correct. My barrel measures .358 at the muzzle. After clearing the muzzle area, I was able to advance the slug down the bore easily until it was apx. 7/8" from the breach end. I then had to seriously pound on the rod to go through. The breach end slugs at .3515. What is next? Shooting jacketed looks like the easiest solution, but who wants easy? Motor, where in "West by God" are you located?

[oldfart1956]

Sadly James this doesn't seem to be unusual in the Rugers. Mainly the Blackhawks but I'm seeing it a lot on the Vaqueros as well. I have an old 3 screw Blackhawk exactly like yours. Just can't bring myself to fire lap it so it doesn't get lead....sad to say. Audie...the Oldfart..

[MtGun44]

How can you measure groove diameter in a barrel with a pin gage?????

You can't. So the groove diam number is not valid, where did it
come from?

Something fishy here.

Bill

[DrCaveman]

What's wrong with fire lapping?

I havent done it (yet) but there are kits out there, at least LBT has one. Might take 20-50 rounds (from what i understand) but can work wonders (so ive heard)

Hey, at least you have identified the problem! Sometimes thats the toughest part

Something funny with the timing of these posts, like they arent showing up before people post responses...that, or people arent reading the whole thread before they post

[Larry Gibson]

What was the lube used?

Was this with a new batch of alloy?

Larry Gibson

[james nicholson]

Larry Gibson, the lube was Jim Conner's "black magic", basically 45-45-10 with microfine graphite added. No not a new batch of alloy, I probably cast these bullets about a year ago, made about 1000 and have been using as needed. They were sized at .358 using a Lee push-thru shortly after cast. I re-lube before loading. All help and advice appreciated.
Thanks, James Nicholson

[SteveS]

In my experience, sizing the bullets to less than chamber throat dimensions will produces leading like you mention. With chamber throats of .359-.3595 I would be sizing to .360, not .358.

I've been working with a Ruger Security Six with chamber throats the same size as yours. I started out sizing the bullets at .358. Leading was noticeable. I started sizing at .359 and the leading was reduced a fair degree. I then started sizing at .360 and the leading is almost gone and accuracy has improved.

This may or may not be your problem but it's something to look at.