how long for bullets to harden

[lotech]

I melted about twenty pounds of scrap odds and ends yesterday and cast a few bullets to measure hardness over time. After about twenty-four hours, samples average 9-10 BHN on my LBT tester. I'm hoping for a final hardness of about 12 BHN as this hardness seems best for my .357 loads. I normally use a mix of known hardness, so I seldom check day-to-day hardness. Will the 9-10 BHN bullets get appreciably harder? Of course, I can always adjust the mix one way or the other.

[waksupi]

Give them a month, then check.

[Winger Ed.]

It's easy to over think some of this stuff, however;

At least a couple weeks for a decent measurement, then they usually slow down for awhile before they finally stabilize.

If you're powder coating or using a gas check & good quality lube, and your speeds are about in the lower-mid 'teens'
it shouldn't matter much as far as leading.

[Seeker]

I don't have a way to check hardness and just go with the adage about cowws as that's all I use for my cast boolits. I can tell you this though....when I water drop for harder boolits, I size them as soon as I can get them dry. I let some sit overnight one time and prit near ripped my press off of the bench getting them through the push thru sizing die. They were very noticeably harder.

[oley55]

From Glen E. Fryxell's book, Ingot to Target here: https://marvinstuart.com/firearm/Manuals/Bullet%20Casting/Fryxell_Book.pdf
Page 31

No matter how I held my mouth I couldn't reformat the table so I retyped the one closest to your first BHN check.


Age Hardening of Tertiary Lead/Antimony/Tin Alloys (In BHN)

97/2/1 as cast-9.2 6hours-17.1 48hours-20.2 6 days-21.6 6 months-18.0
Pure Lead as cast-5 No change------------------------------------------------

[243winxb]

A good read. https://www.totalmateria.com/page.aspx?ID=CheckArticle&site=ktn&LN=RO&NM=88

Oven heat treated bullets, water cooled, with 2% antimony, fully harden in 2 weeks.

[BLAHUT]

Water harden? Or let sit and check every week for a month or so you will get a feel for how long
when they draw for match grade pellets they may let the wire sit for a year or more to stablize.

[lotech]

From Glen E. Fryxell's book, Ingot to Target here: https://marvinstuart.com/firearm/Manuals/Bullet%20Casting/Fryxell_Book.pdf
Page 31

No matter how I held my mouth I couldn't reformat the table so I retyped the one closest to your first BHN check.


Age Hardening of Tertiary Lead/Antimony/Tin Alloys (In BHN)

97/2/1 as cast-9.2 6hours-17.1 48hours-20.2 6 days-21.6 6 months-18.0
Pure Lead as cast-5 No change------------------------------------------------

Thanks for the reminder about the Glen Fryxell material. I've read most of it , though not recently. I loaded for a variety of .357 revolvers for forty years or more, but stopped loading the cartridge at least six years ago, preferring .38 Special loads in all the guns. I once gain became interested in the .357 and loaded some magnum loads with bullets as soft as 10 BHN without problem, something I wouldn't have attempted years back. I had always used bullets of around 15 BHN in the .357 and they worked okay, but doing some bench shooting recently at 25 yards, I found the softer bullets grouped better.

I tried water hardening extensively with both rifle and pistol bullets about twenty years ago. For my purposes, it offered little to no advantages, but I'm sure it's useful for others whose needs are different than mine.

[poppy42]

I don't have a way to check hardness and just go with the adage about cowws as that's all I use for my cast boolits. I can tell you this though....when I water drop for harder boolits, I size them as soon as I can get them dry. I let some sit overnight one time and prit near ripped my press off of the bench getting them through the push thru sizing die. They were very noticeably harder.
Exactly what I do. Made the mistake of letting him sit a couple weeks. Thought I was gonna break my lube sizer

[Hanzy4200]

I will just say, I feel exact hardness is a way over thought issue. I've never checked hardness once. I spitball it every time and have had no problems with leading. Proper sizing and lubing is tremendously more important.

[Cargo]

Would coating the bullets with LLC or PC slow the hardening process?

[414gates]

Would coating the bullets with LLC or PC slow the hardening process?

No.

[pworley1]

I try to size and lube as soon as possible to make the process easier on me and the equipment. I don't think much happens after a month.

[lotech]

I will just say, I feel exact hardness is a way over thought issue. I've never checked hardness once. I spitball it every time and have had no problems with leading. Proper sizing and lubing is tremendously more important.

I'm far more guilty of under thinking than over thinking, but I believe you're right to a point. As stated in an earlier post, I found the 10 or 12 BHN bullets grouped better for me than the harder 15 BHN bullets in .357 loads. Not exactly splitting hairs if you can easily see the difference in group size. For some it doesn't matter; that's fine. All our needs are different.