Comparing Alloys

[kbstenberg]

I have a question for those more exp. than i am with alloy composition an how they react.
If a person has 2 different alloys but they have the same BHN how much differently will they expand when shot into the same expansion media (say wet newsprint)? I'm thinking you mite have an alloy of 75% WW/ 25% pure lead, an the other alloy of 50% WW/ 50% pure lead an add high antimony shot until your alloys equal each other in hardness.
Kevin

[BABore]

Try straight 50/50 WW-Pb and water drop it. Wait 2-3 weeks for it to hardened up properly. It will give you the best expansion of the alloys you mention. The lower you keep the antimony, the better your expansion will be. Get the hardness you want through heat treatment. Water dropped 50/50 will give you 20-22 bhn. Linotype, as cast, will be about the same. They aren't even comparable in expansion media. If 20-22 bhn is too hard for your needs, add more Pb to the WW,s. A 35/65 WW-Pb alloy will still HT to around 15-16 bhn. All bhn values are based on your sorted WW's acheiving 28+ bhn when HT'd. You'll have to tweak the mix if yours run softer.

[runfiverun]

you'd just add enough shot to get back to the 75/25 mix.
if you want a tough boolit that will hold together. then using the least amount of antimony is the answer.
or using a balanced alloy tin/antimony/silver/copper/nickel,with less than 4% antimony is a good bet.
you can avoid all the drama and do like bruce suggests though.
there is also two part/alloy casting.
shooting a softer alloy for hunting only.
de-tempering of a heat treated alloy.
and de-tempering either a water dropped or heat treated boolits nose. to the alloys original bhn.
and finally paper patching the above alloys.

[fredj338]

In your scenario, the two mixes are not the same, so their BHN would not be the same either. In a mix like 20-1 lead/tin & 50/50 ww/lead, the BHN is closer, but they still act diff because of the antimony in the mix. At least w/ LHP, the antimony makes the alloy a little brittle & the expanding "skirt" of the LHP shears or fragments off. The lead/tin alloy is more ductile, even if the BHN is sim. The "skirt" of the HP tends to just fold & bend back. Water dropping the 50/50 ww/ lead mix is a thought. I haven't tried it for LHP, but I don;t seem to get the BHN much above 14-15 w/ that mix water dropped.

[runfiverun]

thats the point of water dropping it's to allow more surface hardness. while maintaining the alloy's malleability.
changing the load to push on it differently can affect your outcome also.