ageing lead

[testhop]

is there any harm in casting up way more boolits and puting them in 50 cal cans
will ageing cause themto become softer or harder stay the same


tom

[wiljen]

The answer is yes. Some alloys get softer over time, others harden, others show little change. I do 30 or 50 cal cans of bullets I use fair #s of, then use a hardness tester and add the hardness measurement at various intervals during the use of the bullets - this gives a nice way to track the hardness as they are loaded and used and shows if any notable change in hardness corresponds to changes downrange.

[imashooter2]

Cast all winter, shoot all summer. Wiljen has a system that works, or you could just not worry about it. There are all sorts of levels to the game, and a lot of what effort you put in depends on what result you want out.

[kodiak1]

No such thing as a bullet to soft or to hard around this place!!!!!
If they came out square would probably try to figure out a way to put them down the range!!!!!!!!!!
Ken.

[Jon K]

They already have figured it out swage, size & shoot.

All lead is good...............

Jon

[smokemjoe]

Takes 30 days to get full hardness, if bullets werent drop into water. I have checked all different alloys and that what I have found. Hope this helps. Joe

[Rooster]

Does that mean that if the boolits were not water quenched that they would have to age a month and then with time get softer? I'm really good at confusing myself in these matters.

[Single Shot]

Depending on the type of alloy and processing, the hardness of a CB can change in either direction over time. Bullets with high tin-to-antimony content will age-soften significantly over many months, even if tempered. To stop or slow down softening, manufacturers adhere to a “rule-of-thumb” of limiting the tin content to no more than the percentage of antimony. High antimony CBs can be annealed (heated and cooled slowly) to reduce their hardness. But given enough time the bullet will eventually revert back to its original hardness. If you cast your own bullets, freeze storage in your home freezer is one trick used to virtually eliminate age-softening or age-hardening.

[Rooster]

Let me introduce you to GAWDZILLA...aka SHMBO. Bullets next to the burger would not go over too well here in Tokyo. But the idea is intriguing. How much would the temperature swing extend the hardness' life? I see old freezers for sale or free all the time, btw what about freezing powders to stabilize them?

[fatelvis]

How much difference in Hardening/softening ,over time, are we talking about? Is it a measurable diference, or a trivial amount? I'm asking because I cast when I "get the bug", and add the newly cast bullets to any bullets cast from the past. Is this a bad practice? Also, I always use WW alloy.

[Ricochet]

Yes, keeping powder in the freezer will make it last longer, too. There are exceptions with some high nitroglycerin content powders that will freeze and crumble at subzero temperatures. That's accounted for gun blowups in Arctic weather conditions. Just keep it in a cool place and it'll last longer than you will.

[454PB]

This is just one of the reasons I prefer using alloy mix to select hardness. I was digging around under my casting bench and found about 20 pounds of 454424 boolits I cast of WW alloy in 1983 (I put notes in with each batch)

The little bit of heat treating I mess with is used up quickly, because it does change hardness over time. Not that the change hurts anything, they are still usable, just that extra time and effort wasted if they aren't used quickly.

[Lloyd Smale]

I dont heat treat or water drop i alloy for hardness and have at least a 1/2 a million bullets in my barn both lubed and unlubed and i keep pretty good accuracy records over the year and have never seen where an alloyed bullet even sitting for 5 years has changed enough to effect accuracy. If a load shot with #2 a week out of the pot it shot the same 5 years out of the pot. I cast all winter to be able to shoot all summer and like to keep at least 2 or three years ahead of myself in case someting happens like did this year with my back. If needed i could right now probably get by for 5 years on what i have without casting a bullet. About the only casting i need to do lately is if i get a new mold and when i get one i cast 3 or 4 coffee cans full of them so im ahead with them too.

[Dale53]

I started pistol shooting this year after a several year lay off. I had several thousand bullets cast, lubed and sized that I have had for several years. They handle and shoot as well as they did brand new.

Hardness does change over time but mostly I ignore it.

Dale53

[Bad Water Bill]

Quick question on lead ageing worste than me. I have about 5k of 22 L R still in the bricks. I got them from someone who quit shooting 40 years ago. Powder and priming still work BUT seems like the lead has swelled to much to fit in the chamber. HELP. BWB :castmine:

[crabo]

Have you made sure your chamber is clean? This would be particularly important if you have been shooting shorts or longs in the gun? Have you tried them in another gun? 22 chambers can be cut to different specs.

[NuJudge]

The bullets were probably large to start with. Most .22 rimfire ammo will engage the rifling during loading into bolt-action rifles, more with match chambers than with non-match rifles. In view of the danger of slam-fires when this is done in a semi-auto, chambers are usually cut larger in semi-autos so as to not have this.

I did not intensively study Lead metallurgy at U of M, but I did study it a little, and various metallurgical property relationships I studied a lot are common to all metals (if they were not common, they would not be metals). There are many ways to harden a metal alloy, three being Solid Solution strengthening, Aging to form Precipitates, and various Phase Change treatments. One that is useful in Lead is trapping lots of Tin atoms in Solid Solution in the Lead crystal lattice, distorting it, and restricting deformation of the lattice. Another is forming Precipitates. On a sub-microscopic level after freezing, what is happening with "Aging" is odd atoms are migrating to where other odd atoms are, and out of the matrix of Lead. The small gatherings of odd atoms are called Inclusions, and are usually in the form of compounds. These inclusions act to restrict the deformation mechanism, thereby hardening the Lead. Different size inclusions do better or worse jobs of restricting the deformation mechanisms. The usual progression is for really small inclusions to not do much. When "Aged" (some combination of time and temperature), the odd atoms traveling to inclusions creates larger inclusions, which work better to a point, then less well. When one gets to the point where it does less well, it is spoken of as "Over Aged."

If you want to know what a Lead alloy bullet's properties will be like in weeks and years, one can put it in a oven at a calculated higher temperature for a calculated time. These processes go Exponentially faster at higher temperatures, or slower at low temperatures. They are also different for different alloy systems, in most useful alloy Steel systems taking geologic age time spans to produce change at room temperature.

We are not dealing with any of the following in a swaged .22 LR bullet. I have read here of dimensional changes that are reported to happen with certain alloying elements in the days after casting. I believe the people describing this. The only mechanisms that I can remember that might explain this would be simple surface oxidation or a change in atomic crystallographic latice arrangement, spoken of as a "phase change." A phase change may cause warping or other dimensional changes. Every pure metal has a certain arrangement of atoms in it's crystals. For Lead, it is "Face Centered Cubic," metals with that structure being known for their ability to accept bending, stretching and compression even at low temperatures. If one adds alloying elements, the crystallographic structure that is stable at a given temperature may change. Sometimes a metal alloy will have one structure ("Phase") that is stable at the freezing or other elevated temperatures, but a different one stable at room temperature. There are Phase Diagrams to describe the equilibrium structures stable at a range of temperatures and compositions. Things get really complicated when one studies how Non-Equalibrium quick cooling will cause still more structures to be formed, which are not long-term stable, and decay over time or with temperature. The diagrams to express these changes are Time-Temperature-Transition diagrams.

CDD

[felix]

Excellent report!!!! Well written. Nothing important is missing that I can see. ... felix

[floodgate]

Bill:

Do the bullets show a covering of whitish "fur"? That is the oxidation NuJudge mentioned above, and CAN increase the bullet diameter enough to jam in a standard chamber, especially if combined with the lube used on plain lead .22 bullets. It can be wiped off with a paper "shop towel", but dispose of the paper safely and wash your hands well after handling; the oxide is a major source of lead contamination.

floodgate

[Dale53]

Bill,
When you wipe the oxidation off a .22 bullet, you also wipe off any lube that may be on the bullet. That can cause major leading. If you wipe the bullets, you will have to re-lube them.

FWIW
Dale53

[Mohillbilly]

Seems like we got a couple'a guys that know their stuff!I got a question,How bout if you were to pack CB in dry ice, would it harden them any useable amount ?

[felix]

No, it won't. It is the rate of change (speed) in cooling is what makes the boolits hard. Dropping them into water from the oven or mold is the easiest method used. No, cold water won't make a difference either because the hot boolit keeps boiling away the water from around its skin. Once the boolit is at 212 degrees where water is water and not steam, the boolit has already gone below 300 degrees where the hardening operation stops. Now, to speed up the hardening process, take the boolits out of the water and place them into the oven at 200 degrees (way below 300) for several hours. They should be fairly ready to shoot after that time, provided the alloy is half way normal, like WW+ maybe some tin. ... felix

[Ricochet]

From graphic data published in the Metals Handbook, accelerated aging with heating of lead/tin/antimony alloys works best if you only do it for 1 hour, age the metal at room temperature for 2 hours first, and I believe (I'll recheck it when I get home) the temperature they recommend is something a bit under boiling water, maybe 200F. The maximum hardness is a bit less than what the metal reaches with room temperature aging, which peaks around 6 days. I retyped a boatload of stuff from the Handbook about this in another thread a few days ago.

[leftiye]

Rick O'Shay, I've enjoyed your information taken from the Metals Association Handbook. I'd like some of the other people here who are metallurgists and otherwise saavy on this subjuct to hopefully comment as to whether this clears up the various theories running amok here on this site (some, a little hopefully). I'm not doubting your inforation, I was an ASM member once for a while, and I am actually hoping this can clear up the fog. Plus having a clear picture would make things vastly easier.

[NuJudge]

I'll be happy to beat the subject of your chosing to death.

CDD

[ssn vet]

Face Centered Cubic, TTT diagrams......Aghhhhhhhh!

NuJudge just took me back in time to a Mech. E. lab long ago......bad! bad! bad! don't torment me any more. I confess!

To bad you chose Blue and YELLOW for your colors. If you'd been a true green Spartan you could have drank more beer and bluffed your way through life by throwing around more colorfull terms like Hexogonal Close Packed rather than writing a real disertation. :)