Revolver leading

[Brad]

First time out with the wife and her new 686 I loaded bullets at .358+ as that is what my GP100 likes. They are big for the .357+ throats on her revolver.
Made a new sizer and it is currently closer to .356 than .357.

With same load, same batch of bullets, and only size being different she shot 100 rounds each.

Bigger bullets leaded the cylinder throats well and the forcing cone and rear 1/4" of barrel. I expected this.

Smaller bullets no lead in cylinder throats but some lead in rear 1/2" or barrel.

Accuracy seemed about the same, smaller bullets impacted lower on target.

I expected smaller bullets to impact higher as they are likely slower and therefore more time for muzzle rise before bullet exit.

I will be making yet another sizer and work for a closer fit to the throats. Rick always says that cylinder throats make a lousy sizer. Actually they make an excellent sizer, you just have to be willing to remove the lead each outing.

Nice I found the right size for the GP100 I can gthpusands of rounds without cleaning. Now to find the right size for the new gun.

 

[Pistolero]

Is this one of the new sleeved bbls. They have a EDM'd barrel and what appears to be the barrel
is just an external sleeve. Apparentl they are wrenched in and out with a tool which engages the
rifling precisely and tightens the barrel in, clamping the sleeve and setting the torque, with no
need to align a front sight.
Brian Pierce has reported that they don't seem to be as cast friendly as the old cut rifled barrels.

If it is EDM'd, I wonder if polishing the interior with a lead lap might improve cast performance.

I have not had leading in the throats in my S&Ws with oversized bullets.

Bill

 

[pokute]

After cleaning, if you stick your finger down in the forcing cone and mush it around, is it rough? First thing I look at in a "new" gun is a rough forcing cone.
Lead in the cylinder throats is something I've never seen. What load?

 

[Rick]

Most likely not leading the forcing cone or beginning of the rifling. Common when bullets too large for the throats shave lead it spreads to the forcing cone and then up the barrel, keep shooting long enough and it'll be coming out the muzzle.

 

[Brad]

158 swc and 4.5 gr HP38 in 38 special cases, CCI std primer.

Forcing cone is a little rough, I can fix that easily.

 

[Brad]

Most likely not leading the forcing cone or beginning of the rifling. Common when bullets too large for the throats shave lead it spreads to the forcing cone and then up the barrel, keep shooting long enough and it'll be coming out the muzzle.

I know. Too big always leads the forcing cone for me.
Now I went too small and it is leading but slightly different. None in cylinder throats, less in forcing cone, but farther down bore.

I think a proper size bullet will eliminate it entirely.

 

[Brad]

Near as I can tell this is not a sleeved barrel. I sure don't see any indications of a sleeve.
I may run a few hundred jackets loads in mag cases thru just to smooth the bore a bit.

 

[pokute]

Most likely not leading the forcing cone or beginning of the rifling. Common when bullets too large for the throats shave lead it spreads to the forcing cone and then up the barrel, keep shooting long enough and it'll be coming out the muzzle.

I see people talk about bullets "too large for the throats" - But if they are too large for the throats, the cartridge won't chamber, will it? OH, WAIT... I see, 38 special case. Now I get it.

 

[Brad]

Not all bullets enter the throats on chambering. I have an MP 359640 that barely starts entering the throats in mag cases in my Gp100. It does lead a tiny bit in the throats if I size a bit big.

This leading is often missed. I find that a snug bronze brush spun in wet and dry patched throats shows it well. Look for swirl marks in the throats under good light. Those marks show a light coat of lead in the throat.

 

[pokute]

Yep, I see. I mostly cast bullets with a nice chunky front driving band.

 

[Pistolero]

The sleeved bbls that I have seen had a muzzle cap that was part of the bbl, and a barely visible
joint between it and the sleeve. The bbl has a "head"on it.

Was is a new, current production pistol, or used?

Bill

 

[Brad]

New, current production. It is marked 686-6

 

[Pistolero]

Here is a photo from the web of the muzzle of one of the
sleeved barrels.

 

[Brad]

This gun has a flat muzzle with a minimal crown. No recess like that at all.

I see no indication that this is a sleeved barrel.

 

[fiver]

I wonder how they are securing that shroud.
I guess simple like Dan Wesson uses is too much trouble, it's gotta be something the end user can't play with.

 

[Pistolero]

Interesting. I wonder if they have left some of the production with their
old bbl design and switched some over. Or whether they have decided to
drop the two piece bbls.

Good luck sorting it out. Perhaps a few hundred rounds of jbullets to smooth
the bore may help.

Bill

 

[Brad]

I wonder how they are securing that shroud.
I guess simple like Dan Wesson uses is too much trouble, it's gotta be something the end user can't play with.

Yes, factory work only I am sure.

Can't have people monkeying around with their own guns....

 

[Pistolero]

696 is a .44 Spl, IIRC. Assume a typo.

The shrouded ones would take a cast in "wrench" in the field, I would think.

Bill

 

[Brad]

No, this is a 686.
I fixed the type Bill, thanks.

Looking online it seems only certain models got the sleeved barrels.

 

[Pistolero]

OK, it would seem that with the extreme accuracy that I have with my 586 +1
and others have with 686s, changing the bbl design wouldn't be smart.

Bill