Lubes, hard alloy, soft, & other mysteries

[JohnFM]

OK, here we go.
This all relates to a 357 S&W 18-3 4 inch model.
I've fired lots of commercially cast 158 grn bullets through this thing.
Those things are hard, with a pretty hard lube in the lube ring. They all measure right on .358.
Usually use 13grns of 2400.
Leading is hardly noticeable, just not an issue.

My mold drops straight COWW at ~.3585, sizes through a Lee sizer at .358.
With tumble lubed LLA, sized or unsized, and the same powder load, the leading is terrible.
Boosted up to 14grns of 2400 the leading is decreased. I can follow that to a point, the bullet is obturated more and sealing the bore tighter.

I staple my targets to old cottonwood blocks and after they begin to get used up I split them apart and recover almost all the lead in them.
Sometimes the spent bullets are hardly damaged. I notice evident melting on the bases of the WW bullets, the really hard commercial ones have basically pristine bases.
Is the melting of the softer lead adding to the leading in the bore?

Or is there a better lube on the commercial ones?
I've got a lot of linotype, would I get to a cleaner bore by going towards a harder alloy?

I know bullet fit is talked about here all the time as the most important thing.
But with something like a 357 options are limited.
Never seen a mold advertised as casting something like a .359.
The barrel on my 18-3 slugs at ~.3572.

[Larry Gibson]

You might try adding 2% tin to your COWWs. You may be seeing more antimony wash than leading with just the COWW alloy. The addition of the tin will help with that. The alloy will also be better, the BHN will be 14 - 17 after 10 days when AC'd and they will probably cast a bit larger so that you might be able to size at .359 or possibly .360. That alloy will be much better for magnum level loads. If you are shooting .38 SPL or mid level loads then you can also cut the WW + 2% tin with lead to soften it to a 8 - 10 BHN for very good results and more bullets for the WWs you have.

For "fit" with a revolver you want the bullet to be the same diameter as the cylinder throats. However, as you've seen with the .358 commercial bullets if the lube is good they can also shoot very well and not lead even if they don't "fit" the throats as well.

Larry Gibson

[JohnFM]

OK. I could use some of my supply of linotype to increase the tin content?
Didn't know I could expect the mold to throw a larger diameter.

This S&W has a nice cylinder, all the throats are identical and a perfect match to the bore.

[runfiverun]

part of it is the t/l design.
and the alox.
you are comparing apples and oranges here.
the t/l depends on the boolit being big enough to obturate the bore and it has no sealing properties whatsoever.
it also by design has less bearing surface to grip the rifling,and small bearing bands that will gas cut quite easily with nothing in there to combat the gas or repair the breach.

try not sizing them.

[JohnFM]

Not sure what t/l stands for, but I've pretty well decided not to size any more of these 358-158-RF bullets for a while.
At least as long as all I have is the Lee sizer, at .358 it makes a purty bullet, but seems like it cuts the size awful close.

[geargnasher]

You changed alloy, boolit design, and lube all at once, and the LLA is a very, very inferior "lube" for what you're trying to do.

Gear

[JohnFM]

Haven't changed anything yet. In fact haven't even cast anything for a while now.
Just thinking about it.
So, why is LLA so inferior?

[geargnasher]

Your gun just told you why. Now if you were using, say, a light charge of Unique it would probably work ok provided you used two, thin coats.

I don't get it the part about "haven't changed anything yet". You said you fire commercial 158-grain, pre-lubed boolits through it and have no real problems. The you cast some from COWW and lube them with LLA, and you have big leading issues with the same load. What does that tell YOU?

Gear

[JohnFM]

Doesn't tell me anything. I expected some commercially cast lead bullets to function at least close to how they should and they did.
If people can cast and lube with LLA and get good results, I'm looking for what the next step should be to get my casting to perform, first off reducing the leading.
Harder, softer, heavier lubing, lighter lubing, a different bullet?

[geargnasher]

If changing three things and having failures afterward doesn't indicate that one or more of those three things is the problem, you should probably drop back to step one and do some studying. Google "lasc (dot) us" and look up the on-line book From Ingot to Target by Fryxell/Applegate. Read every chapter, then you'll know what's going on with your gun. I can tell you all day, but if you don't have the reference knowlege base it won't really help you understand very well the problem your gun is having with some of what you're feeding it.

Gear

[runfiverun]

it does tell you something, you just don't see it.
re-read this thread and think about what has been said.

[JohnFM]

You all are too cryptic for me.
I'll figure things out with what written material I have.

[btroj]

You did change something. Pulsed a different alloy, a different bullet design, and a different lube. Any one of these, or a combination of them, may have been the source of your leading.

Let's start with something simple. Larry mentioned it may not be leading but what we call an antimony wash. Did you get lumps of metal in the throat end of the barrel or did you just notice a light grey color in the bore when looking into the muzzle? True leading is usually a lumpy fouling in the throat on a revolver. Runa dry patch down the barrel, you can feel it.

How did the bullets shoot? Were they reasonably accurate? Did they allow a long string with consistant accuracy or did they start shooting worse as you fired more and more of them? For a handgun load I like to shoot at least 50, sometimes even 200 in a session to see how a load really does over the long haul.

the LLA is not a great lube for higher pressure and velocities. The tumle line (t/l) style bullets also seem to be best for lower pressure and velocity round. Use the search function here to read up on Recluses 45/45/10 formula, I think it is better than straigh LLA and is easy to use. A very light coating is all that is required.

I do not think you're "melting" the bases of your cast bullets. Many of mine will show little "impact craters" on the base when using a plain base bullet with a Niger pressure load. This just doesn't matter.

You have some options. Try Recluses 45/45/10 lube. Try water dropping your wheel weights to increase the hardness. You could use 50/50 wheel weights/pure lead for a softer bullet. Try using your bullets in sized. Do NOT try all these at once. Change only one thing at a time. Changing one thing at a time allows you to know how that specific change made a difference for the better or worse.

The answers you were given here were all very correct. These people told you exactly what you needed to know. Shooting and casting bullets is not something you can just pick up and do quickly. We all hit road bumps like this at times. It is the learning process that matters. Figure out why each thing changed made a difference. What changed and why it mattered.

Nobody here can magically say "do this and it will work" as too many guns have proven us wrong. It doesn't matter what happens in our guns with our bullets, it only matters what happens in your gun with your bullets. Learn to listen to the fun, it is telling you all you need to know. LEarn to understand what it is telling you.

Yes, this can all be cryptic. Part of the learning process is understanding how the various factors interact.

[JonB_in_Glencoe]

here is a great resource for Alloy info.
http://www.lasc.us/CastBulletNotes.htm

I don't have a quick way to check your load for what pressure it might be.
But I suspect the hardness of alloy is your problem, that's where I'd start.

Air cooled COWW has the following capability according to the link above
25,000 PSI - Non-Magnum handgun loads, Rifles to 1,900 fps

either water cool your COWW boolits or heat treat or add lino.
read through the link, it has other great info.
BTW, for future reference, the link is one of the banners at the bottom of this page.
I look at it often.
Jon

PS. another option is dialing back your loads, I like Unique as gear suggested.

[Elkins45]

You all are too cryptic for me.
I'll figure things out with what written material I have.

What they are saying is that there are many differences between the two results you are comparing. When comparing your results with the commercial bullets to your home cast results there are at least four things that are different:

2 different bullet designs
2 different alloys
2 different diameters (probably)
2 different lubricant formulations

In changing to a different bullet you actually changed all four of these factors. Any one (or more) of them could be the reason for your different results.