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Discussion Starter · #1 ·
OK, all of you Super Blackhawk owners, here is a question for you.
I met a fellow reloader yesterday at the range and we chatted quite a bit. He had this problem.
He has a Super Blackhawk in 44 mag with either a 7 or 7 1/2 inch barrel. He said he can't shoot lead bullets in it because it leads up immediately. After the first round fired it accuracy gets increasingly worse. He has tried lubed bullets with each kind of lube, PC bullets, hard coated bullets. He has used hotter loads as well as lighter loads. Flat based bullets conical based ones, you name it he's tried it and still it leads. He said it leads from the forcing cone to about 3 inches down the barrel. He shot down every suggestion I could think of, having tried them all already. He has a friend who has a Super Blackhawk like his and the friend shoots lead all the time with no leading. I told him I would contact a Ruger tech and see if they could come up with any ideas. What do you guys think?
 

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Are the bullets hard enough? How about sizing? Has he tried gas checks?
 

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I would bore slug the barrel. Then run slug back thru and see if first part of bore is tighter or looser than the rest of the bore.



But first contact Ruger.:)



Jim
 

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Ruger's customer service is top notch. I agree with the idea of talking to them before going further.

The barrel on the SB I used to have was fairly rough.
Soft lead bullets leaded like crazy, even at lower velocities.
Hard Cast Lead Wide Flat Nose Gas Check bullets kept the leading down to a minimum at max velocity.

I've read that you must remove all jacket fouling before shooting lead bullets to avoid leading.
(I've never been able to remove all jacket fouling from any firearm so...) :dunno:


:usa:
 

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Leading at the forcing cone can be caused by the bullet being over sized and swaging down as it enters the forcing cone. It can also be caused by being out of time. In the latter case, the leading is on one side and the revolver normally spits lead. Yet another cause us a roughly formed forcing cone.

Leading after the forcing cone is almost always caused by a constriction in the barrel caused by too tight of a barrel-frame thread. Slug the bore, you will feel it getting tighter as you reach the area of the barrel-frame junction. This is an easy fix by fire lapping which will cure it in short order.
 

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Discussion Starter · #6 · (Edited)
Are the bullets hard enough? How about sizing? Has he tried gas checks?
I suggested GC's, don't know if he's gonna try them. He said he's using 18 BHN and a friend of his suggested going down to 12 BHN. I told him I'd go harder. He said he's pushing them at less than 900 fps.
 

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Discussion Starter · #7 · (Edited)
I would bore slug the barrel. Then run slug back thru and see if first part of bore is tighter or looser than the rest of the bore.



But first contact Ruger.:)



Jim
He's planning to slug the bore.

MB and greg_r, I'll pass your suggestions along to him, thanks to all.
 

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.44 Rem Mag:
I have shot thousands of full power .44 Rem Mag with my own cast 10-13 BHN bullets with NO leading.
In general:
Leading that starts at the forcing cone or at the beginning of the rifling is due to the alloy being TOO HARD or the bullet being TOO SMALL.
Leading that starts and follows the leading edge of the rifling is because the bullet is TOO SOFT or the velocity is TOO HIGH.
Leading that starts mid-way or later is because the lube has failed.
Now, for revolvers, you have an additional issue:
The bullet must, at a minimum, be a SNUG slip fit in the cylinder's throats. An undersized bullet will start gas cutting in the throat and things just get worse.
Next, the forcing cone needs to be reasonably smooth.
Finally, the bullet as it enters the rifling must almost always be at least 0.001" LARGER than the ACTUAL groove diameter.
So, if the gun meets SAAMi dimensions, the throats should be 0.4325-0.4365". Using bullets smaller than 0.4320" can lead to gas cutting even in the smallest throats SAAMI allows.
Next, the groove diameter should be 0.429-0.433", so the bullets should be 0.001" larger than this.
However, you will note that one can have the small throat and the large groove and have a gun that can't possibly shoot lead well unless the factory or gunsmith opens up the throats.
Finally, when I have leading with stupidly HARD alloys, a light tumble lube in LLA will cut the leading to nothing (or almost nothing).
SAAMi specifies a 0.4320" lead bullet, but I find that is often too small. That dimension is for safe operation in every gun, but isn't a good choice for most. Get larger bullets, after determining the throat and groove dimension, but, I must say, if coated bullets are leading, you have another issue (may be the forcing cone or improperly cured coatings).
 

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Slug the barrel! Iv'e been shooting cast bullets for 48 years with very few leading problems when the projectile fits the bore!
 

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I just bought a new Ruger 357 Vaquero and ordered pin gauges to check the cylinder throats and the bore. The throats were .358 and the bore was .350 without the pin gauge binding where the barrel screws into the frame. Meaning Ruger did a very good job and the throats and barrel should fire cast bullets without problem.

I plan on firing 200 to 300 jacketed rounds to break in the barrel and then try some cast bullets and see if the barrel needs to be lapped.

Larger calibers will have thinner barrels and can be constricted or choked when tightly screwed into the frame and cause leading.

Bottom line the cylinder throats should be the same diameter as the cast bullet. And the barrel should be smooth and not be constricted.

After firelapping the bore you will have tapered rifling and improved accuracy without any leading.

[FONT=Arial, Helvetica]A Contemporary Look At Barrel Leading and Related Sixgun Issues
http://www.gunblast.com/FerminGarza-Firelapping.htm

Firelapping Stainless Steel Ruger Handguns in 36 Rounds[/FONT][FONT=Arial, Helvetica]
http://www.beartoothbullets.com/tech_notes/archive_tech_notes.htm/47
[/FONT]
 

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The BORE may be 0.350", but what is the groove diameter? You still need to slug the barrel (see Google). You need to be at least 0.001" larger than the GROOVE diameter.
 

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Discussion Starter · #12 ·
Gave him suggestions from all of you. Haven't heard back from him yet. He said thanks for all the info.
 
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