lead aging and hardness

[silverback13]

ok guys, relatively new to this process so be kind at my naivety. If am looking for a bullet to be about 9 to 10 bhn at the time of use. I get source that is 9 to 10 at the time of casting. My understanding is that as time goes by the bullet will harden. Any info on how long (days , weeks, months) does it take to stabilize to its final hardness? also what are the average hardness differences in water dropping and air cooling.

I know that water dropping will generally produce harder bullet but to what degree harder than air cooled?

now with this premise if one wants to shoot a bullet that is 9-10 bhn they should get lead that is much softer prior to pouring and wait for it to stabilize.

[Dusty Bannister]

Lead and tin mixes age soften, and tin, antimony and lead alloys age harden. An ingot of any of the mixes or alloys might be about the hardness of a cast bullet when it has matured. Higher ratios of antimony age harden slightly faster. Check your PM's.

[JonB_in_Glencoe]

The short answer is, if you're casting for pistol plinkers and the alloy is advertised at 9-10, you have nothing to worry about, just cast 'em, lube/size 'em, load 'em, shoot 'em. No need to wait and no worries about waiting too long
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If you want to learn some more, here is a fun filled thread of varied answers
http://castboolits.gunloads.com/showthread.php?122354-Question-about-ageing-boolits-for-hardness

Post # 8 from the above link (by Bret) is about as good an answer as you'll get without offering more details about your alloy content and your casting procedure.

My experience- I've found that hardening takes place over a 2-3 week period with AC tertiary alloys. With WQ they harden much faster, achieving their final Bhn in a few days. Different alloys seem to react differently. The softening thing? Takes years. I have boolits I cast in the late 80's that are still within a point or 2 of what the box states they were.

To throw in a monkey wrench- each alloy will have a different level of "hardness" or "toughness" no matter how you treat it. Using just the Bhn tells you a limited amount about how the boolit will perform. Yes, I've said this before, yes, I know it's boring, yes, it's a pet peeve of mine. But Bhn isn't the whole story.

[runfiverun]

air cooled usually sets up to it's bhn in about 14 day's.

water cooled takes about a month to get near it's final bhn, it will wander up and down over that time.
you have to have antimony in the alloy for it to water quench.
if you have a bhn of 12 it will water drop from a 375-f mold to about 22 bhn.
if you get the alloy hotter [oven] and the water colder you can make the bhn go up even higher, a 12 bhn alloy can go up near 30.
you can also draw down the bhn using this method by adjusting the temperatures of the oven and water.
this is of course assuming a tin/antimony/arsenic/lead [or similar] alloy.
add in bismuth or copper and things can change.

[bangerjim]

You did not tell us what alloy you are casting. Makes a BIG difference!

I see and plan on a 3+ increase in air cool hardness. I PC everything, so I do not really worry about exact hardness anymore. Anything 9-12 in subsonic is fine with PC.

Water dropping with a high Sb alloy will increase the hardness a bunch! As a test, I WD in COLD water (water from the swimming pool @ 55F) a couple 12oz ingots of Hardball-ish alloy and ended up with a reading of 36+! After 4 weeks it went down to ~30 and stayed. Waaaaay too hard for what I do. But I just had to find out what it did. Air cooled stayed at around 22.

I mix my alloys from scratch for the hardness I want because baking the PC on at 400F for 10 min pretty much eliminates any WD hardness.

banger

[silverback13]

i can't thank you guys enough for all the info. I am new to casting process and trying to match the right BHN to pressure. I haven't started casting yet as i am gathering information and shooting others bullets.

from what i gather to acheive good obturation the optimum bhn at 14000 psi would be 9 to 10 bhn. i am not shooting anything over these pressures.

now i have to read all the information provided to try to get a set a standard for the lead mix's i purchase or scrounge.
i