How long after casting before sizing and or shooting

I did a little reading and searching and I did not find a lot on this, just a few very old threads. For my purposes I am using an unknown alloy with a BHN of around 13, melted down bullets. The bullets are being cast and air cooled, then powder coated and air cooled.

From my reading my understanding is that air cooled bullets harden over time, vs water quench, which hardens right away then softens.

So a couple questions related to air cooled bullets.

How long should you wait before sizing?
How long should you wait before you shoot it?
How long for the lead to be fully stable in its BHN?

I understand you can short cut things sometimes, with minimal ill effect. Looking more for what is ideal vs what you can get away with although both would be good to know.

I have seen people say they size right away as the bullet are softer and it is easier. I have tried this and have flattened and or smeared grooves. I have seen advice on sizing to wait 24hrs to 3-4 days. I have seen people say to wait at least 1 month before shooting but not in detail as to why. But to my understanding this should be based on what the lead is doing which I have not seen explained.

I've sized and loaded them as soon as they were cool enough to handle. Mostly its a lot longer between casting and sizing. I can't tell any difference.

I make my pistol bullets from an alloy (lead-tin) that runs about 10 bhn, and my rifle bullets from Lyman #2 (about 15-16 bhn). I size them all within one day of casting then load them all season long. (I cast in the nov-jan time frame and shoot the rest of the time). Never noticed a problem.

When testing I cast and size in the same hour.

Various alloys will harden some after a couple weeks.
Unless you're getting way out on some ragged edge of the boolit's performance limits,, it doesn't matter how new or old they are.

I remember a commercial caster advising me to wait two weeks before even loading his casts. He even had a note in every box saying the same. Now that I cast and coat my own, loading and shooting is a couple weeks after the bake, since there’s enough heating to resoften the alloy.

I do several batches of boolits over a week or so; if I know I’ll be using the new production soon I date the batches and use oldest to newest.

Scientificly... it takes two weeks for bullets to stableize in size and hardness. Yes the can grow. That only applies to antimony leads. The grain boundaries are reforming and changing. Its the fastest in that two weeks.

Over time they will peak out and then soften. I dont remember that time frame but i do beleive its longer than a year.

Know science class over and back to reality. Do you need to wait that long. I try too. But sometimes, expessially with pistol bullets. I will cast size and load that day then shoot the next. I have cast sized and loaded riffle rounds and then shot them the next day. The perfectionist in my tells me not too and to follow the established process, but if you deviate it wont hurt nothing. I dont push the envolopes though so i dont need supper duperd hard bullets and BHN of 10 will do me but i prefer a 12. For some reason i like quenching 9mm bullets. Just feels right.

I have really only heard of it being an issue for ammo that has sat for an excess of over a year and i think it was a tight chambered gun to begin with. I size my bullets to throat diameter and havent had anny issues yet (knock on wood). But i got some ammo i need to light off that is over a year old. But if i get a mysterious round that wont chamber i will know why.

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I found my BHN 12 as cast go to BHN 16 after two weeks.

never really worried about it. I used to cast a load of bullets then in the days after lube size a batch at a time them reload whenever
lately since I got my casting pot set up right next to lube sizer, I'll cast a bunch, usually a spinach can full then lube size. them maybe go to reloading room to drop them off and put a couple together for test fire and make sure I can at least hit the broad side of a barn with them.

I like to size sooner than later. Bullets will harden a bit as they age making sizing a bit more difficult. IF PCing, then a day or 3 after baking.

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Originally Posted by fredj338

I like to size sooner than later. Bullets will harden a bit as they age making sizing a bit more difficult. IF PCing, then a day or 3 after baking.

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▲ this, though I do size the same day as I cast and will finish the next day if the sizing runs long

Not really to you question but I try to keep a good stockpile of bullets: when I load them I soon will cast so I have a good supply that has time to harden. Usually have 1K-2K on hand (mostly cause I like to cast)

With harder antimony stuff I wait for two weeks before I load or shoot.

I often size and coat right after casting. Or coat and size. Or size,double coat and size like for a 470 NE. Depends.

About bullets growing,yes, last year I melted some big 500 S&W bullets from 2004... they had grown too big to chamber and were crazy hard , impossible to size. They were 50 monotype/50 WW.

I have been casting for over 40 years and never paid any attention to the age of a cast bullet or noticed any difference in shooting or sizing. They could sit for a day or a month or a year before I size and lube. After that, they could sit weeks, months, or years in the cartridge before being fired. Life's too short to stress about it unless you are after very precise results for target or match use.

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Originally Posted by HWooldridge

I have been casting for over 40 years and never paid any attention to the age of a cast bullet or noticed any difference in shooting or sizing. They could sit for a day or a month or a year before I size and lube. After that, they could sit weeks, months, or years in the cartridge before being fired. Life's too short to stress about it unless you are after very precise results for target or match use.

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Yep

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Originally Posted by Shadow9mm

I did a little reading and searching and I did not find a lot on this, just a few very old threads. For my purposes I am using an unknown alloy with a BHN of around 13, melted down bullets. The bullets are being cast and air cooled, then powder coated and air cooled.

From my reading my understanding is that air cooled bullets harden over time, vs water quench, which hardens right away then softens.

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That's a bit backwards. Lead alloys age harden by a secondary precipitation process, which generally requires a solution anneal first (heat and rapid quench), followed by time for the internal precipitates to form. Bullets that are air cooled may never harden, as you don't have the super-saturation caused by rapid cooling that drives the precipitation.

https://i.postimg.cc/jd8MSpDG/Lead.jpg

I cast with a 50-50 mix clip on wheel weights and soft scrap lead , air cooled .
I size with a Lyman 450 - boolits sized the same day or the next day size easiest .
I have learned to try and get them to drop as close to the diameter you want them sized as possible , the less squeezing down the easier your life becomes . NOE has some "Fat" diameters if you need larger boolits . Trying to squeeze down a fat diameter , say .360" down to .356" is hard on you and sizer ...buy another mould .356" ... Any way , back to hardness .
After one week they are about as hard as they get ... Another week they might harden a little more but at two weeks they are done getting harder .

I try to size my air cooled boolits the next day because they are so easy to size but usually it's the next weekend . I'm in the middle of sizing a batch cast last year ...the truth is cast em' when you can , size them when you get some more free time and load and shoot when the weather allows .

I first noticed the same day hardness vs next month hardness with some RN 9mm luger boolits and a flat nose punch , sized the next day the flat nose punch left a nice .15" diam. flat spot on the boolit nose , a little RF if you please ... did more a few weeks later and no flat spot was left ...the boolits were hard enough not to be flattened ...there might have been a tiny .05" diam. mark left ... and I could feel the boolits were sizing just a tad harder .
Gary