Oven Hardening

[tmattox]

I'm new at the art of casting. I've casted about 50 292 & 480 grain 45-70 bullets. My lee hardeness tester says they're about 10-12 hardness. I've been told that you can oven harden a bullet. How is this done? Do you oven harden it before of after you run it through a sizer? Any help is appreciated.

[just.don]

http://castboolits.gunloads.com/showthread.php?t=108966&highlight=oven+harden

[sqlbullet]

That thread is a good read.

The TL;DR version is this.

Put them in a 400° oven (verified by thermometer, not the dial) for 1 hour. From the oven quench them in water Less time in open air better.

I accomplish this without the oven by dropping the hot boolits from the mold into a bucket of water. If you cadence and mold temps are consistent, this will yield just as good a result.

If you are going to oven-treat the bullets, then size first. Working lead softens it. There is significant debate about how much, if any, impact this actually has on the bullet, but if you are going to heat treat in a separate step, might as well size first to remove the debate.

Finally, if you heat them and then let them air cool in the oven back to room temp rather than quench them, you will remove any heat treatment. This will give you a base line hardness against which to measure all else.

Also, the bullets will wander some after heat treating. Waiting a week is advisable to test. Any stock that has sat for more than 6 months should be tested as well.

Finally, hardness is not the end-all. Load them and shoot them. See if your gun likes them. No sense in doing extra work if they shoot fine like they are.

[Wayne Smith]

Nobody has said it, so I will. Depends on your alloy. +antimony,-arsenic will act differently than +antimony, +arsenic, and different amounts of each will change your result.

[captaint]

tmattox - First, welcome to the mayhem. Second - just a suggestion, but you might try shooting the boolits you have as they are now. Could be you'll have fewer issues with the softer, rather than harder. Depends on many other factors, but sometimes it pays to leave them on the softer side. Folks do get caught up in the harder, harder, harder thing as being better. Not necessarily so. Maybe shoot some of each and compare. Just my .02. enjoy Mike

[leadman]

I agree with captaint, unless you are pushing these extremely hard they will probably shoot just fine.
If you cast these less than a week ago they probably will gain some more hardness with time.

You do need an alloy with arsenic to oven heat treat them. Like clip on wheel weights or shot.

[popper]

I size after HT for GC's CBs, before for PB. You'll need your alloy to have > 2% Sb for much effect.

[RobS]

Some more info:

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