Question.

[CWLONGSHOT]

I discovered I have access to a friend of a friend who owns a company who deals with lead. Now he dosent know bullets or BHN or know lino manynof the names we have for our alloys and mixes. He knows chemical content. He has offered to test a lead hardness I like and produce me ingots in that composition. IE that hardness.

I was excessively low on soft lead and he really helped me in that regard last night. In speaking with him afterwards he has Antimony paste. (?). He is gonna give to me today. He wants melt with the pure he gave me and try, then add more try, until I get what Im wanting.

He said its a 6% antimony.... So the product he is giving me is pretty darn hard. Im gonna breaknout my old 10# pot. (Its clean and better suited for small qualtities Ill be "testing")

Myquestion is whats a good target to start at? Meaning a pound of pure and a ounce of 6% or 6 oz of 6%??
My target is actually two targets. First good alloy for pistol say maybe 9/10 BHN and 15/16 BHN. (Pistol/low velocity pressure and Rifle moderate vel and pressure) Personally speaking I have no use for very much at all over 2000 fps. If I do Ill use jacketed. Cast for me is lower cost fun and lower vel pressure.
As a side note Something I already have "down" is my 20:1 alloy I like for my HP bullets in handgun velocities (under 1200 fps)

Thanks guys!

For some reason wrapping my head around this escapes me.

I thought you might appreciate the pic he sent me with the quote " Is this enough?"

 

[Brad]

Almost all of my shooting is with an alloy around 1.75-2% Sb. That is plenty for my needs.

Use 2 parts pure to 1 part 6% and you should be good.

 

[Rick]

Brad is correct and with a 2% Sb alloy if you should ever need/want something harder it will easily heat treat.

 

[CWLONGSHOT]

Ok yes forgot to ad that as a question. Would This non heat treat ally @ 10 quench to say 25? Im correct in understanding YES?

that Sure makes it easier!
CW

 

[Rick]

Quench from the mold to 25? No! Would require oven heat treating to reach that.

 

[Brad]

The great thing about heat treating, with a PID controlled oven, is that YOU can control BHn reliably. Heat for an hour to 375° and quench for one hardness, 400° for an hour get a little harder.
I bet that with PC heat treating won’t be nearly as important

 

[CWLONGSHOT]

Quench from the mold to 25? No! Would require oven heat treating to reach that.

OOPS. TYPO!!!

15!!
Yea I know Id not see close to 25... Probably even in a oven!

CW

 

[Rick]

2% Sb properly oven heat treat can easily reach 25 BHN. With all the heat treat testing I did I never did find either a use or a need for anything that hard, not even in the 454. Also too hard can and does lead to a decrease in accuracy and possible leading.

 

[Rockydoc]

Will an alloy of lead and antimony without arsenic heat treat?

 

[Ian]

Yes. Arsenic in a Pb/Sb alloy is a grain refiner which increases the hardening effect of antimony during rapid cooling by controlling the size of the shear planes that form. Think of lead as concrete, antimony as rebar, and arsenic as reinforcing mesh.

Tin bonds with antimony in like molar quantities to make the intermetallic Sb/Sn which is tougher and harder within a Pb alloy than either element alone. Never add more Sn than Sb though because the sequwnce of crystallization will leave free tin in the mix and will diminish the returns.

 

[Rockydoc]

Yes, but my question was: will lead/antimony with no As, no Sn or anything else, heat treat harden? It was my understanding that Pb/Sb would not heat treat without As.

 

[Rick]

Yes it will. As isn't needed to quench harden. Look at As in the alloy as frosting on the cake, better with it but not a requirement. It's the sudden freezing of the Sb by quenching that is required.

 

[Brad]

Cast bullet alloy and the role of arsenic, sulfur, Selenium and copper

From the pages of The IHMSA News, Shooting sports, hand gun, ammo, cartridges, xp 100, reloading, firearm, cast bullet, bullet casting and more information articles

www.lasc.us

 

[Brad]

If you want to add a little As just use a small amount of shot. Most shot has As because it helps give rounder pellets.

 

[CWLONGSHOT]

What about addin magnum shot to harden things up??

any formulas?

CW

 

[Brad]

magnum shot can vary in Sb content based on brand and pellet size. I would add a small amount, like maybe 5% of total mix, and call it good.
I can assure you that my range scrap has very little As if any and it heat treats very well.

 

[Tomme boy]

Anwser a ? for me. I was always told that factory foster slugs were about 5% Sb. They are extremely soft. When you cast ingots of just them they look like the lead has a galvanized coating. I was also told it was to help the lead flow on impact.

Is this wrong?

 

[Brad]

Lead flows better under pressure with Sb and no Sn. Fiver has often commented that lead pipe is not pure at all but rather has some Sb to help the forming process.

My understanding, and I am hardly an engineer or material sciences expert, is that it has to do with grain size. The large Sb grains mean fewer grain interfaces. The fewer interfaces the easier it is for the metal to flow. Sb hampers it by reducing grain size so more energy is required to make the metal flow.

And now you have a bases for why some allows work better for some bullets. I will let Ian explain that one better.

 

[popper]

Lead pipe, sheath, etc has a problem called cold flow. So Zn or Sb is added. As causes HT hardness to occur more quickly. Best case for 2% BHN probably 20ish.

 

[Ian]

Antimony makes lead tough yet remain ductile to a point (about 2.5%), much than that and it makes lead brittle. Tin makes lead a little tougher while remaining malleable, but it loses ductility because tin makes it shear when drawn. Add both to lead and the result is the best of both worlds if that's what you want or need, which usially you don't.

It all has to do with dynamic fit. Sometimes you need a bullet to be able to draw out and conform, sometimes you need it to be tough and resilient without being brittle.