Leading...

[shane8168]

I was loading Dardas 125 gr RN 9mm in .357" for my Ruger SR9C with 4.3 gr Unique and I never experienced ANY leading problems. I probably shot 1500 of those and never noticed any lead in the barrel, in fact I wondered if I was missing it because I didn't know what to look for.

I switched to W231 when my Unique got too smokey and bulky for my preferences. Now loading the same bullets for the same gun with 4.3 gr of W231 and after about 150 of those I have lead in the barrel...

So, what causes the leading in my barrel?

 

[454PB]

The choice of powder would not cause leading. What diameter are these boolits?

I own four 9mm handguns, and I use .357" for all of them. Most 9mms need a larger cast boolit for accuracy and leading prevention.

 

[ljnowell]

The choice of powder would not cause leading

It sure can.

 

[Walkalong]

But this time it is probably a pressure difference. W-231 usually plays well with lead.

Where is the leading at in the barrel after 20 or so shots? The first inch or so, the whole barrel?

I would think 4.3 of W-231 would be OK, but it obviously isn't. Since 4.3 of W-231 will be hotter than 4.3 of Unique, you might try 4.0 Grs W-231 and see if it gets better or worse.

 

[GP100man]

Well 231 is a bit faster than unique & your probably skidding the boolit .

By skidding I mean the pressure pushes the boolit faster than it can engage the rifling thus skidding & leaving a groove open for gas to blow by then gas cutting is finishing the leading process from chamber to muzzle .

If ya can recover a boolit & look at the engraving it`ll give a better picture of what`s going on than I can describe !!

According to Hodgdon`s site your running .4graines aver recommended.

http://data.hodgdon.com/cartridge_load.asp

Slow it down a bit & all will fall into place as before the powder change .

 

[41 Mag]

You might try Universal, it will give you about the same pressures and velocities as Unique, but not as much smoke and crud.

The 231 might be a bit much in the initial pressure dept and might be causing the bullets to hit the lands a bit harder than the Unique did which can result in the plating rupturing.

 

[LiveLife]

When I did my initial load development for Missouri 125 gr RN bullet, I referenced current Hodgdon load data for 125 gr CN bullet and worked up to 4.4 gr. and I got leading along the rifling of Lone Wolf barrels at higher charges.

125 gr LCN W231/HP-38 OAL 1.125" Start 3.9 gr (1009 fps) 25,700 CUP - Max 4.4 gr (1086) 31,200 CUP

Lyman #49 showed 4.4 gr as max charge for 120 gr LSWC and 4.1 gr as max charge for 120 gr LRN.

I then referenced 1999 Winchester load data for 124 gr RN bullet and it showed 4.0 gr as max charge. As Walkalong suggested, I would conduct a powder workup from 3.3 - 4.0 gr and see how the leading is, especially since you are using larger sized .357" bullet instead of more typical .356" sizing.

Another thing to consider is the bullet nose profile (ogive) and how deep the bullet base gets seated in the case neck. Dardas 125 gr RN bullet has a stepped nose and Dardas 124 gr RN bullet has a shorter, more rounder nose like the Missouri 125 gr RN bullet. If you are using the shorter rounder bullet with longer bearing surface, the bullet base will get seated deeper in the case neck with shorter OAL (which increases the chamber pressure) and you may consider using slightly less powder charge.

Dardas 125 gr RN vs 124 gr RN


As to the burn rate of W231/HP-38, I also successfully use 4.0 gr of Promo (using Red Dot load data by weight as indicated by Alliant) referencing 2004 Alliant load data for the same Missouri 125 gr RN bullet. Promo/Red Dot is faster burn rate powder than W231/HP-38 and I do not get leading in the barrel of Lone Wolf barrels. Below are pictures of LW barrel after several hundred rounds of 4.0 gr Promo load - as you can see, no leading in the barrel, just residual lube smearing.

 

[GimpyLeg]

Good write up BDS!

 

[454PB]

Yeah, a too heavy charge can cause leading, but that's not the fault of the powder.

 

[shane8168]

Okay, now what I really need is a picture of what "leading" really looks like. I cleaned my barrel already, but I think it looked like those in your picture which you call "lube residue".

I never noticed that when using Unique, but see something like that (it might really be "leading" afterall) now when using W231.

 

[918v]

By skidding I mean the pressure pushes the boolit faster than it can engage the rifling thus skidding & leaving a groove open for gas to blow by then gas cutting is finishing the leading process from chamber to muzzle .

No such animal.

 

[918v]

I agree it is a pressure issue. Unique has a more gradual pressure vurve than 231 with that powder charge weight. I use 3.7-4.1 grains of 231 under a 125 TCFP in my 9s. But I also make sure the bullet is a tight fit in the freebore. I dunno what your setup is so I can't comment further.

 

[LiveLife]

Okay, now what I really need is a picture of what "leading" really looks like

This is from Glen Fryxell's ebook on leading from Chapter 7 - http://www.lasc.us/Fryxell_Book_Chapter_7_Leading.htm

Leading is the deposition of significant amounts of bullet metal on the bore. It can take many forms -- streaks, chunks, splotches, films, etc. (more on this in a minute). It's important to recognize that the mere presence of streaks in the bore is not an indication of leading; many types of bullet lube (especially the commercial hard lubes) leave perfectly innocuous streaks in the barrel that have no negative impact on firearm performance (if a wet patch removes the deposit, it probably wasn't lead). Nor is a gray "haze" on the bore surface necessarily a problem; it can be an indication of a leading problem, but it can also be simply a reflection of the alloy of barrel steel used, how the rifling was cut, or a reflection that the barrel isn't "broken in" yet.

What shows on my picture is darkened residual lube smearing and not leading - it is readily removed by Hoppes #9 solvent.

Much more on definition, location and cause of leading on the link.

 

[ljnowell]

Good posting BDS!! I always enjoy your posts. Sometimes when I see a leading thread I start to put a reply then stop and wait a little bit to see if you do.

 

[noylj]

1) A hard cast lead bullet as Missouri supplies is not going to strip on the rifling.
2) A powder is not going to cause leading--unless you are using TiteGroup, which burns HOT and can heat up the barrel quite a bit over just a few rapid fired rounds. Even then, TiteGroup generally plays OK with lead.
I have heard some complain that 231/HP38 leaves "sand" in the barrel. I have never seen this, or cared, and it doesn't sound like this is your problem.
3) Fit (a lead bullet at least 0.001" larger than the barrel's groove diameter) is everything.
4) If you run a few wet patches through the barrel and then a dry patch or two, you can see the leading as patches/streaks of metal different from the barrel. The location of the streaks will tell you what the problem is.
If it appears near the chamber, chances are that bullet diameter or hardness are the cause. A diameter too small or an alloy too hard will allow high pressure gas to leak past the bullet, which erodes the bullet and leaves leading near the chamber.
If the leading first appears on the leading edge of the rifling, the bullet might be too soft or the velocity too high.
If the leading appears in the second (front) half of the barrel, the bullet is running out of lube.

I hope this helps.

 

[Walkalong]

I pretty much agree with everything noylj posted.

A post on Leading.
.

 

[918v]

2) A powder is not going to cause leading--unless you are using TiteGroup, which burns HOT and can heat up the barrel quite a bit over just a few rapid fired rounds. Even then, TiteGroup generally plays OK with lead.

I disagree. The powder is a variable that contributes to leading. It affects pressure, how fast it rises, how the bullet obturates the freebore, the velocity, etc.

Some powders are more forgiving than others.

 

[GP100man]

The OP used 12bhn boolits & if ya go much over 1150-1250 with em the alloy will give just enuff to let gas cuttin begin .

Agreed if ya gonna use lead they gotta fit , but alloys have there limitations & the OP has obviously surpassed it by a bit !!

Nice pic of the bore !!

I recommend this :

 

[LiveLife]

OP is using Dardas cast bullets and they are advertised at 16 BHN. OP is using bullets sized at .357" and did not get leading using Unique but got leading when switched to W231 at 4.4 gr. It looks like OP is pushing the bullets too hard and if a powder work up from start to max of 3.3 to 4.0 gr (I would even do an initial testing of 3.8 - 4.0 gr) shows decrease/elimination in leading, it would confirm the suspicion.

loading Dardas 125 gr RN 9mm in .357" for my Ruger SR9C with 4.3 gr Unique and I never experienced ANY leading problems ... switched to W231 ... and after about 150 of those I have lead in the barrel ... So, what causes the leading in my barrel?

 

[Ky Larry]

I haven't had any leading isuses in any of my guns since I started following Missouri Bullet Company's advice on velocity and hardness and started using Lee Alox. Also, I use AA#2, 5, and 7. I load 9mm, .38Spl, .357 Mag, .40 Smith, .44 Spl, .44 Mag, and .45 ACP.

 

[918v]

The OP used 12bhn boolits & if ya go much over 1150-1250 with em the alloy will give just enuff to let gas cuttin begin .

Not true. Gas cutting has nothing to do with the alloy being too soft. Gas cutting only happens when the bullet is too small and too hard to obturate.

 

[Hondo 60]

I recommend this :

Take a Chor-Boy or other COPPER scrubbing pad.
One strand wrapped around a brush or mop. enough to create a tight fit in the barrel, will scrub away any leading in just a few passes.

This is severe leading!

 

[Walkalong]

Gas cutting can also happen when the bullet doesn't hold the rifling and breaks the seal.

 

[GP100man]

Skidding ^^^^