Can someone explain this

[PAT303]

I cast up a heap of CBE 225grn bore riders for my 303's and oven quenched them,after doing it I didn't think the temps were right so I reheated them again,quenched and loaded them over 30grns of AR2206H (H4895) which has been my standard load for ages and they shot all over the place,when I say all over I mean all over,some hit the 100m berm,others cleared the 200m and hit the ground quarter mile behind.Back home I tested them and they came out at 8 brinnel,the alloy was WW/solder and range scrap-pistol boolits and it usually comes out at 20+.So did I heat treat them the first time and anneal the second?,8 brinnel is softer than ACWW. Pat

[JeffinNZ]

How soon after quenching did you shoot them? They will take a good week to come up to 20 BHN.

[44man]

Sounds like pure lead, the stuff will not harden.

[Wayne Smith]

Yeah, we really need to know the alloy you used. Could be close to pure or may be impatience. Whatever the cause it was way too soft.

[PAT303]

The alloy was WW,bar solder and range scrap,stupid thing is I cast a heap more today,oven quenched them and two hours later they are 14 Brinnel???.How could the ones cast last week be 8,I checked boolits from both lots 5mins ago and sure enough last weeks double heat treated ones are 8 and todays single heat treated ones are 14,same alloy,pot,temp,molds etc etc.I don't get it. Pat

[243winxb]

The double heat treating moved the tin to the outside of the bullets, maybe ??? How long did you have them in the oven? 1 hr. or more? 2% antimony will take 2 weeks to fully harden. 6% antimony will harden in 1 hr after heat treating, water cooling. Less tin is better for oven heat treating/water cooling.

[DonH]

I'm no metallurgist but to my knowledge, if you heat treat most any metal then reheat it you will probably draw the hardness to a degree (somewhat softer) if not outright anneal it. If you went from 20 bhn+ to 8bhn~, you likely annealed them. Have you tried the heat treat process again on some of those bullets to see what hardness reading you get? Just curious.
and maybe you didn't wait long enuff. From NRA Cast Bullets, Suppl. 1, page 5 (Cast Bullets For Africa?) a table shows hT'd bullets from two aloys - one was 3# ww to 7# lead while the other was straight WW. Bhn readings shown were taken at ~ 18-19 days after heat treating. The softer alloy came out ~ 20 bhn while the WW came out ~ 29 bhn.
Updates please?

[PAT303]

I reheat treated all the boolits last night,after 12hrs six tested at 20 brinnel,I might stick to doing it once properly from now on. Pat

[Sonnypie]

I believe I'd find a bigger berm.
Keep them boogers from getting away. :kidding:


I'm fond of the old Lyman #2 formula. It's about 16 BHN water dropped for me.
90/5/5
Don't know if that is reasonable for you. But 90 pounds of lead, 5 pounds of Antimony, and 5 pounds of tin.
Or lesser amounts like 9# lead, .5# of Antimony, and .5# of tin.

I shoot that out of a 30-06 Springfield caliber, which is pretty close to a .303 Caliber.

I don't always hit the bulls eye. But I never miss the berm. ;-) :kidding:

Cheers! :grin:

[DonH]

I reheat treated all the boolits last night,after 12hrs six tested at 20 brinnel,I might stick to doing it once properly from now on. Pat

Thanks for that info. Until you began this thread this is something I just hadn't thought about. It's good to know "what if".

[paul h]

Have you tried quenching right from the mold? I'm a lazy caster and anything I can do to elimminate steps I do. So long as you drop them hot out of the mold they'll get nice and hard.

While you do need to allow the bullets to age to reach full hardness, they are still much harder than air cooled bullets immediately after quenching.

[shooter93]

You un-treated them. Charlie Dell did alot of experimenting with heat treating and then heating again to "draw" the bhn back. He was interested in exact hardness through out his match bullets and very closely monitored time and temperature.