Same BHN, Different Alloys?

[ChristopherO]

The alloy calculator I found here today is pretty amazing. There is much to learn for one who has only cast pure and Lyman #2 in the past. Figuring out the variations on how to obtain a specific BHN is fascinating but I am surmising there is more to it than just the hardness of the bullet. Taking the various percentages of tin to antimony to lead that configure to create a 12 BHN out of 5.6% tin, 1.8% antimony and 92.6% lead is probably going to respond differently when hitting hide, bone, meat and organs than the same designed boolit with a 12 BHN created out of coww of 0.5% tin, 2% antimony and 97.5% lead alloy. As the tin and antimony content diverges to even greater percentages the expansion, or non expansion properties probably change to a larger degree, as well.
Am I correct in suspecting that the terminal ballistics of 2 like kind bullets with the same hardness rating made out of two completely different types of alloys will not have the same kind of dynamics or am I over thinking this?

[bangerjim]

Overthinking a very simper thing. Plug in the alloys you have and go with it. Change the amounts to arrive where you want to be. Simple, it does all the math for you.

Just mix (to whatever you feel your hardness should be), cast and shoot!

I PC everything, so I shoot much softer lead ( NEVER #2!) than I used to! FIT IS KING today, not hardness.

banger

[Yodogsandman]

Yes, you're correct. Different alloys will act differently. Try to use equal amounts of tin to antimony for the best results. Adjust the amounts added to pure lead for your desired hardness. Any hardness over about the Lyman #2 equivalent of 15 BHN is easier (and cheaper) to get by either water dropping from the mold into cold water or oven heat treating and quenching in cold water.

There's a lot of great information on this over on the Los Angeles Silhouette Club site.

http://www.lasc.us/castbulletalloy.htm

http://www.lasc.us/heattreat.htm

[ChristopherO]

Thank you, gentlemen, for your replies. Having had experience with pure and #2 I am leaning now toward a 12 BHN, which can be obtained with the soft plumber's lead and linotype on hand. Yet, the tin/antimony ratios will not be uniform, to say the least. Makes me wonder If I should go another route.

[RobS]

Not to worry a great deal about the tin being a little less as long as you have proper boolit fill out which often times takes a bit hotter mold temp. I almost never use tin with WW alloy and there is only about 1/2% in it to begin with before casting etc. However there are some molds that just don't cast well without tin or if a person wants to make an alloy that is tougher or bonded then tin works nicely. One thing is to not have more tin than antimony as been already stated as it can somewhat solder itself into your bore under certain conditions.

[RogerDat]

Lino+WW's+ a little Solder can be combined to equal Lyman #2, Hardball is 50/50 linotype and plain lead with about the same BHN. Using some stick on WW's for the plain will provide some arsenic to help with water dropping or heat treat and quench.

Water quench of hot lead changes the grain structure so harder without an equivalent increase in bullet fragility.

[ChristopherO]

[QUOTE=One thing is to not have more tin than antimony as been already stated as it can somewhat solder itself into your bore under certain conditions.[/QUOTE]

What? More tin than antimony will cause issues? This is the first I am hearing of this. So a mixture of 5.6% tin, 1.8% antimony and 92.6% soft plumber's lead is not a good combination to achieve a 12 BHN bullet? This is getting more complicated all the time.

[bangerjim]

What? More tin than antimony will cause issues? This is the first I am hearing of this. So a mixture of 5.6% tin, 1.8% antimony and 92.6% soft plumber's lead is not a good combination to achieve a 12 BHN bullet? This is getting more complicated all the time.

Just do it the way everybody else does. Don't re-invent the wheel on hardness mixing!

It is a TOTAL waste of a very expensive metal...SN!!!!! At $10-20/#, you only want/need 2% max. Sn does not add the hardness nearly as much as Sb. Use Sb to gain hardness....Sn for mold fill-out only. There is some "magic metallurgy" that occurs when mixing Pb/Sn/Sb. This has been covered amny times on here and on LASC. If I remember right, it takes 15X the amount of Sn to get the same hardness increase as Sb.

Just use the alloy calc to get to your hardness based upon Pb/Sb.....then add 2% Sn for good fill-out. You are totally overthinking this thing and making it waaaaaay to complicated!

banger

[Yodogsandman]

Just guessing that you have linotype and pure lead. Linotype is about 12% antimony (Sb), 4% tin (Sn) and 84% pure lead (Pb). So, if mixed 4 parts pure lead to one part linotype and then 2 % tin added, it should be close to 12-13 BHN air cooled for a few weeks. Add a little chilled or magnum shot in that alloy to add some arsenic (As), then oven heat treating/quenching could get your alloy to about 24-25 BHN (after 5 days) and be just as ductile. Be sure to check my figures with the alloy calculator, just in case.

What alloys are you working with?

[ChristopherO]

You're close. Linotype and very soft plumbers lead. I'm thinking 12 BHN as Lyman#2 is pretty hard from past experience but it needs to be stout enough to travel down the barrel at 1600fps+ in a 4570. Not wanting a solid as I like a little expansion to the bullet. .