PDA

View Full Version : When will my boolit get hard enoug to load ??



gray wolf
04-16-2013, 12:35 PM
May I ask a question here ?
if you air cool the castings how long do they take to get hard enough to size and load so they don't reduce in size when seated in the cases ? I have some .432 44 mag bullets a week old that are 50/50 WW/PB they have a 1/2 pound of mono added to every 10# of the mix, the cases are expanded with a .4295 expander and when I pull a bullet they are .430 I need them to stay .432
the bullets drop at .433 and are sized .001 to .432
When do these bullets get hard ?? Water drop are hard like a rock the next day and maintain there size. I would like to air cool, am I not waiting long enough to load them ? am I sizing to soon ? am I dong something wrong ? never had this happen before. But I don't remember how long I let the air dropped sit around before loading them.

Sam

MtGun44
04-16-2013, 12:40 PM
I air cool all mine, no problems. Air cooled are the hardness that they will
be once they cool down, no harder with age as far as I know.

Water cooled take some days or weeks to fully develop the hardness.

Either you need a larger expander stem or harder alloy or to use the
water dropped boolits. I do not water drop for any pistol ammo, including
.44 Mag and .357 MAG.

Bill

fecmech
04-16-2013, 12:49 PM
I don't think a week with that mix will be fully hardened but pretty close. A WAG at your mix for hardness would be BHN 10-11 and with .004" case pull that may not be enough to keep them from getting smaller. You can accelerate aging by raising the temperature of the bullets by leaving them in the sun(if you have any!)all day for a couple days or put in the oven for a couple hours at 150-170 deg.

gray wolf
04-16-2013, 01:10 PM
you need a larger expander stem
the cases are expanded with a .4295 expander now, how much bigger can I go until I loose any frictional hold on the bullet ? I don't want to depend om maybe a 10% hold from the roll crimp.
I see it as I have .0025 frictional hold now.


put in the oven for a couple hours at 150-170 deg.
I thought to oven harden you did 400 or 450*F for an hour and then quenched in cold water. Are you saying that 170*F for 2 hours and than air cool will harden them ?

Case Stuffer
04-16-2013, 01:25 PM
Have a look here,about half way down is an Age Hardening chart

http://www.lasc.us/Fryxell_Book_Chapter_3_alloySelectionMetallurgy.ht m

detox
04-16-2013, 01:34 PM
Min of 3 days with antimony alloys
http://www.lasc.us/SuperHard.htm

gray wolf
04-16-2013, 01:55 PM
Some very good reading,
a little hard for me to take it all in at once but very helpful.

Thank you

Larry Gibson
04-16-2013, 02:03 PM
I always suggest 7 - 10 days for most ternary alloys. However, if the neck tension of the case is enough to over come the BHN of the AC'd alloy then there will be some sizing of the bullet. You have to balance the amount of neck tension with the BHN of the AC'd bullets. The .4295 expander may work well with some brass cases and not others. Depends on their "hardness" also.

Larry Gibson

rintinglen
04-16-2013, 02:59 PM
I always suggest 7 - 10 days for most ternary alloys. However, if the neck tension of the case is enough to over come the BHN of the AC'd alloy then there will be some sizing of the bullet. You have to balance the amount of neck tension with the BHN of the AC'd bullets. The .4295 expander may work well with some brass cases and not others. Depends on their "hardness" also.

Larry Gibson

Quite true. Older, work-hardened brass will be more troublesome in this regard than new, properly annealed brass. A BPCR Silhouette competitor of my acquaintance anneals his match brass everytime before loading it, in part to avoid this very problem. The more times that you size and shoot your brass, the harder and more brittle it becomes.

fecmech
04-16-2013, 04:15 PM
I thought to oven harden you did 400 or 450*F for an hour and then quenched in cold water. Are you saying that 170*F for 2 hours and than air cool will harden them ?
You are not heat treating you are accelerating the aging process. Age hardening can be slowed by cold temps and sped up with heat. In the case of water dropping bullets. If you don't want to size and lube them right away, by placing them in the freezer you can keep them at the same hardness as when they came out of the water for at least a week. Makes things much easier on your sizer!

gray wolf
04-16-2013, 04:38 PM
You are not heat treating you are accelerating the aging process. Age hardening can be slowed by cold temps and sped up with heat. In the case of water dropping bullets. If you don't want to size and lube them right away, by placing them in the freezer you can keep them at the same hardness as when they came out of the water for at least a week. Makes things much easier on your sizer!
Now that's interesting, I wondered how that worked, thank you.

cbrick
04-16-2013, 06:06 PM
Min of 3 days with antimony alloys
http://www.lasc.us/SuperHard.htm


Some very good reading,
a little hard for me to take it all in at once but very helpful. Thank you

That's a brilliant author Mr Wolf and a right nice guy too, I know him well. :mrgreen:

Roto Metals has that article linked on their web site.

Rick

243winxb
04-16-2013, 09:29 PM
the cases are expanded with a .4295 expander and when I pull a bullet they are .430 I need them to stay .432
the bullets drop at .433 and are sized .001 to .432 Using a Lee factory crimp die?