Hardness not tell the whole story?

[phigaro4570]

Has anyone found that an alloy of equal hardness, but containing much more tin or antimony, leads less than WW or WW/Pb alloys? I'm getting more leading than Elmer Keith using plain base bullets even though I have tried hardnesses ranging from BHN 11 to 20. Without telling all the details right here, everything seems like it should be perfect. But, I get leading just forward of the forcing cone and wonder if 5-6% Sn and the same of Sb (like Lyman #2)would perform differently even though the hardness is the same. Hardness is resistance to deformation. Could chemistry change resistance to abrasion?

[cdngunner]

My guess is your bullet is not sized right....composition is not the end all to leading.

Slug your barrel and see what size it is....bullet should be two thou bigger.

You could also try a gas check

[Outpost75]

My experience in revolver loads is that most leading is caused by bullets being too hard and undersized. When in doubt, go larger and softer. Factory soft-swaged lead bullets are about 8 BHN and can be approximated by alloying 50-50 wheelweights and plumber's lead, with a small addition of tin, not to exceed 2% to improve casting quality. This works very well up to .38 Special +P and Ruger .45 Colt loads up to about 20,000 psi in revolvers and similarly up to about 1300 fps, for full charge loads in rifles such as the .45-70, .44-40 Winchester and .32-40.

It has also been my experience that soft lubricants work better than hard. Typical cast bullet lubricants work by the boundary layer principle and their effectiveness depends upon their ability to flow and coat the bore. The hard lubricants used on commercial bullets are that way mostly for ease of handling through automatic loading machines. When you recover fired bullets with full lube grooves that is a "clue." I would rather see a nice black, slimy grease star on my muzzle and look down into a wet, sooty, bore than a gray dry, dusty one.

You can do much worse tan to mix your own lube using 1 part of Dexron automatic transmission fluid to 4 parts by melted volume of pure yellow beeswax.

Size revolver bullets to cylinder throat size, NOT to barrel groove diameter.

[BK7saum]

Is there any thread choke in your barrel? Sounds like your boolits might be going through the thread choke and are leading when they hit the larger diameter in front of the thread choke.

[phigaro4570]

The cylinder throats are .432", groove is .430". I've tried my bullets at a fat .432 (meaning a shade over that) and they were a hard enough push through the throats that you would have to mount the cylinder in a vise and pound with your palm. Sized at .4315 or so, they are the pencil push tightness I have read about. Both these sizes will lead. My bore has been smoothed and lapping slugs have been fired so I think the barrel constriction is gone. That gas check would probably be the cure, but I have read so many old writings sounding like leading is no problem, and they all used to use what is now a terribly expensive amount of tin. Or the old Lyman #2 having much alloy metal.

I've got some bar solder I could make up a small batch of alloy with and just thin it later if it didn't reduce leading. And I thought about getting some superhard to get 5-6% Sb by thinning. I just thought someone may have already tried these things. 6% tin gives me a spasm in my hip pocket, but so do gas checks.

[Master_Mechanic]

Had a 629 lead in the same spot, cylinder throats were undersized compared to the bore. Measure the throats and the bore to determine your sizing. Leading is 9 out of 10 sizing or lube related.

[phigaro4570]

Oh yeah, I forgot to say I've used Veral's blue lube and sometimes have coated LLA/JPW over that, and sometimes just the blue lube. I recently gained confidence in my crimp, too. So I'm pretty sure I'm stopping as soon as I feel the rim has crimped into the groove. So, I'm pretty sure I'm not causing bullet damage by overcrimping and then the damaged bullet sheds lead.

[Master_Mechanic]

What load are you using?

[Outpost75]

How hard are your bullets?

[tomme boy]

Didn't old Elmer run all of his boolits at around 10-12 for hardness if I remember right????

[phigaro4570]

My bullet is the .44-250-K and at first I was using 3 parts Pb : 1 part WW. I think I tried this alloy both AC and WQ. Hardness of this alloy is pretty soft when AC, maybe around 10 or 11. When WQ and aged a couple weeks it gets almost as hard as straight WQWW, up close to 20. Later I went to straight WW and WQ and the accuracy seemed to greatly improve. I've tried 18, 19, and 20 grains of 2400 and 19 grains shot as well as I can hold for two cylinders of slow paced shooting. Yes, I think those SWC's of Elmer's were supposed to be 16:1, which is around 6% Sn and I think the hardness is around BHN 10 - 12. I'm about ready to put pencil to paper and see if gas checks would be cheaper than buying more alloy metal, anyway. If the gas checks would be cheaper, then there is no use testing to see if the other alloys would lead less, except, of course, curiosity. I have a Ranch Dog .44 mold that takes a gas check and it would probably be very good.

I sure was fond to try the PB SWC and 2400 powder after reading "Sixshooters". The stories about the ornery critters and men in that book are worth reading even if you were not interested in the guns. And he was a small man. I expect he held his own with horses and men, though. You can tell from his stance in the pictures that it's what's between his ears (and under that big hat) that makes him what he is.

[Larry Gibson]

No, BHN is not the "whole story". Malleability is the "rest of the story". The ternary alloy (lead, antimony and tin) need to have a balance of tin to lead which then goes into solution in the lead. Having too much of either or both does not a good alloy make and can indeed lead to leading or antimonal wash. Very good Ternary alloys have fairly equal parts of antimony and lead from 2 1/2% each up to 5% each. This allows the antimony and lead to form the sub metal SbSB which then goes into solution with the lead. More than that of either does not really improve the malleability of the alloy (note how brittle antimony is). The metallurgy articles in the Lyman CBHs explain all of this.

If you are using COWWs then add 2% tin to them. You may then cut that alloy by adding lead and still maintain a balance of tin to antimony. However, the COWWs + 2% tin makes an excellent alloy for Kieth type .44 magnum AC'd bullets and with a proper lube they can be shot to magnum levels with excellent accuracy and no or very minimal leading. The BHN of those bullets should run 13 - 17 depending on the quality of the COWWs. The alloy also maintains excellent malleability.

Larry Gibson

[phigaro4570]

Thanks Larry! Yes, I remembered reading of this balance of Sb and Sn in the alloy in my old CBH. Honestly, it was such thick and sticky reading that I did not feel I could understand and rightly use it. And it never does explain why (I don't think) it is good to have pretty equal amounts of Sb and Sn, but I'm ready to give it a try, understand it or not.

It reminds me of my college days and words like "stoichiometric". Believe it or not, I still remember Avagodro's number. (I understand that, but haven't made a lot of use of it.) I was guessing that the Sb-Sn bond that was strong contained equal numbers of atoms of both elements. It bugged me that the atomic weights could be different enough that the weights proportion would be noticeably different than 1:1. But I just looked them up and, the weights of Sb and Sn are about 121.7 and 119 respectively. For my purposes that's the same weight.

All this to say, without trying Elmer's full 6% Sn, I can bump my stingy 1% Sn that I currently use, up to 2% and try that. Larry, you sound like you have a handle on this chemistry that I still lack. I'm thinking WW are supposed to have 3 or maybe 4% Sb and a smidgeon of Sn. So, really, I could probably add a little more than 2% Sn to make the two alloying metals equal, right? I was guessing 3% would be closer to equal. And really, I don't actually know that Sb and Sn tend to group up in equal numbers in whatever chemical equation describes this.

I have just one curiosity left about your experience, Larry. Have you actually observed a "balanced" alloy not leading, while an unbalanced Pb-Sn-Sb alloy of the same hardness did lead, with everything else about the load being the same? I sure appreciate your sharing what you've learned, and if I ever know anything relevant I'll sure share it. I've got work that needs to be done on my house and this might be some hours at the lead pot and loading press that you are saving me.

Thanks again,
Jerry

[Larry Gibson]

Current testing of COWWs have shown the actual antimony content to be close to 2.5 % on average and the tin content to be .5% at the most with many newer WWs having 0% tin. That's why adding 2% tin most often balances out with the antimony content formingSbSn sub metal.

Yes I have observed leading but most often antimonal wash with unbalanced alloys high on antimony content. Leading is most often a function of poor lube, not enough lube, poor fit/no obturation to throat or simply pushing the a softer alloyed bullet too fast. I prefer to avoid leading and antimonal wash simply by using a proper alloy, known lubes of provn performance, proper powders that ignite easily and burn efficiently for the cartridge and use bullets of correct design. Not that difficult to balance an alloy of unknown exact contents simply by BHN testing and understanding the necessity of balancing the antimony with tin. It's when some want to be "cheap" and avoid what they think is costly tin that we see alot of problems. Some also simply think mixing linotype with COWWs solves the tin problem but they don't realize they are adding a higher % of antimony and exasperating the problem.

It's not all that difficult to cast and shoot bullets w/o leading or antimonal wash. The problems seem more prevalent of a problem these days of powder shortages and alloy shortages where everyone is mixing up there own from unkown metals such as range lead, current COWWs scrounged lead, etc. Also the advent of many home made lubes and lube modifications exasperates the problems as does the desire for faster cast bullet velocities. A antimony rich and tin poor alloy can indeed cause problems which can not be solved by "fit" or with another lube.

Larry Gibson

[prs]

I also appreciate Larry's refresher tips. Sn is $$ and I may skimp a bit, limiting mine to 2% by weight which may be close to 2.5% by volume. Wheel weights are NOT what they once were, but if you can get the large truck or bus type, they seem to be more like those of bygone years. When judging how alloy changes effect leading, it helps to use a known to be effective lube as a standard. For that, NRA 50:50 seems a logical choice. Another factor that might effect the relationship of toughness/hardness/malleability is post cast aging. Patience may well be a virtue as the inherent or ubiquitous arsenic trace knits its matrix through the casting.

prs

[phigaro4570]

I sure will try bumping my Sn up to 2%. Up to now, I thought that 1/2% to 1% would get you all the filling characteristics that could be had, and any more than that was a waste of Sn. I will certainly try this higher percentage out for a while and, of course, permanently adopt it if I can tell any difference. That would be amazing to me to see tin reduce the leading while the BHN remains unchanged.

Without having to melt any lead or cast any new bullets, I am able to try out the gas checked Ranch Dog .44-265's I already had laying around. The group I shot with them today was too big overall, but three holes touching at 45 yards. (I honestly know that I cannot be that good even if everything else were perfect.) Much to my relief, there was no leading. I have a variation on that ready to try as well as some shot buffer under the .44-250-K. The shot buffer is something I don't hear much of, but Veral Smith talks well of it.

[phigaro4570]

I molded up some .44-250-K's today with the WW + 2% Sn. Without having yet shot them, I can say they look like an airbrushed glamour photo of my cheap, low to no tin, alloy bullets. They just look really smooth due to so few pock marks, and they poured this way at 700 degrees or a little under instead of the usual 800 or more that I used to use to try to get them to fill out. Also, whether the alloy directly caused better bases, or only indirectly by allowing a lower casting temperature, the bullets didn't have holes torn in their butts from the sprue tearing out. I WQ'ed some and AC'ed some and will try them in a few days.

Having more Sn in the mix makes me more concerned about my fluxing, now. I can't help feeling like I am oxidizing something when my paraffin bursts into flames and keeps burning. Part of me wants to snuff out the flame, feeling like I will oxidize less tin if I do so. Does anyone know if this is correct? Then I wish I could be sure that anything dry and ashy can't be oxidized Sn when the flame goes out. I'm familiar with the skin that needs to be reduced back in, but not sure that none of the dry ashy stuff is Sn oxide. I sure thank you guys for helping me find a tool to reduce my frustration.