Lead alloy effects in swaging

[Metroxfi]

Do different lead alloys change the expansion characteristics in jacketed swaged bullets?

I'm sure everyone knows that lead work softens, so lets say I took some straight clip-on wheel weight alloy and cast up some cores. If I then take those cores and work them down once in a core swage die, then again in a core seat die does the antimony content offer any difference versus say, stick-on wheel weight alloy processed the same way? Once the clip-on alloy is worked enough would it act comparably to pure?

For example, in swaging bullets from empty 22LR cases would you get a more violent/frangible expansion from starting out with a soft lead like stick-on wheel weights? Or, would the difference in performance between clip-on and stick-on lead be negligible due to the amount of work softening?

I'm familiar with the effects of alloys in cast solids and hollowpoints and the effects of tin versus antimony in cast expansion but all that would seem to go out the window when you start working the material.

On the other hand, has anyone ever played around with heat treating lead-antimony alloys after fully forming the bullets? Let's say you made some jacketed open-tipped bullets using clip-on alloy for cores. Once fully formed you put in an over at about 475*F for a time then remove and quench in water, theoretically you'd harden the core significantly. I don't think you'd gain a whole lot from doing so except possibly increase your penetration. Actually, thinking about it, that might be something to play with. Leave the core unbonded so it would shed the jacket relatively quick while a hardened core drives deep. You may also be able to "time" the expansion with different levels of heat treatment, bring to temp and air cool for a core with 10-12BHN that way the core won't splatter so much and may hold together a bit.

Sorry guys, it's a slow day at work and I'm daydreaming. Let me know what you think, or if you've played around with different alloys.

Thanks!

[uncle dino]

I use different lead tin alloys..because the bhn is stable and doesn't harden with age.. I have not been able to detect any work softening of lead/ tin alloy in the swaging process. Not that it doesn't happen.. I just have not seen a difference. I do not think enough lead is moved to completely work soften the entire bullet...maybe parts of it.. But not the whole bullet..a swager has more control over expansion and terminal performance by varying the jacket..thickness and length to control expansion. To the point where a super hard heat treated alloy is typically not needed.. D

[DukeInFlorida]

I use lead as close to pure as I can. It work hardens/softens less, is more stable, and less of it is needed to achieve final weight. It also flows perfectly in the jackets. It doesn't beat up on the tools.

[runfiverun]

if you heat a pointed up bullet till the lead melts it will squirt all over the place.
I have taken to melting my cores in the jackets then water dropping them as soon as the lead solidifies.
pin tumbling.
then point forming, with just enough core to make the nose flat.
this is for 30 cal stuff I'm trying to get to penetrate better.

for my 22 stuff I want to explode violently.
thin jackets.
soft lead core.
and exposed lead at the tip make that happen.

[reed1911]

I use pure or 1/2% SB here as well. On the little calibers it is easier to use harder lead, but it is also easier to blow a die up, there is this exact thing noted here:

http://castboolits.gunloads.com/show...gers-Nightmare

On larger calibers, you can forget it on a hand press. Try to swage a BHN of 8 in .45 cal and you will quickly drop that idea. If you want less explosive effect then the easiest way is a thicker or harder jacket or a doubled up jacket. Thin jackets and soft jackets will expand faster. As Runfiverun said exposed lead will expand faster. You can also vary the tip diameter, a larger hollow point or more flat nose shape will expand faster.

If you are bound and determined to use a hard alloy I would Cut yourself a mold that will do it, and just use the cores as cast and see what you can core seat, just be aware that you will likely break a punch in the process and plan accordingly. The problem with heat treat is that you may alter the dimensions of the bullet and then once water dropped you will not be able to re-point. Regardless, once you get to a certain point all you will end up with is a fragmented bullet at impact which if that is what you want, just go soft and let the bullet expand to the same point. Or they will act just like a FMJ in which case, just swage a FMJ and skip the hard lead.

A good question and completely logical regardless so take no offense at anyone pushing you to something else, there are just easier ways to accomplish what we think you are after.

[Sasquatch-1]

I was the OP on the thread Reed1911 linked to. Swaging hard lead can be costly. It ran me just under $120.00 to replace the die body I broke. I am still doing it but using a lot more caution when putting pressure on the handle. I will pull the handle down until I feel a good resistance release the handle and apply pressure. I repeat this until I get the shape I want. If you have to push hard on the handle it's too much pressure. Takes a little longer but will save money in the long run. Also, this is reshaping only. When doing jacketed I use dead soft lead.

[Metroxfi]

Thanks for the responses guys.

I'm not wondering how hard of lead I can use to swage, i'm wondering if using harder lead even matters because of the work softening.

I had read somewhere, possibly this site, a long time ago where the author was talking about the differences between precisely cast cores and cores cut from lead wire. He stated that he had a noticeable difference in expansion, even with the same alloy, due to the lead wire being worked a total of three times (cast ingot extruded to wire, wire cut and swaged in bleed die, seated in jacket) and the cast core only being worked once (cast core seated in jacket). Apparently the bullets with the lead wire cores would absolutely explode while the cast cores would deform and fragment but still be recoverable. It's been at least four years since I read that and I don't remember where I found it.

Runfiverun, when I mentioned heat treating a full formed bullet I didn't mean melting the lead inside, I meant to treat it like you would a regular cast bullet you're trying to heat treat. Put them on a tray in a little convection oven and get them up to about 475* and quench them.

I'm currently making .224" and .243" bullets on a reloading press and using nothing but rimfire cases for jackets. A couple years ago I traded a ton of .224" 55gr to a local gun shop to try out and told them to let me know how they work for them and to let me know if they shoot anything interesting. Well, it had only been couple weeks when they told me a story about a coyote hunt they went on. A coyote popped up close to them as they were walking and he was able to squeeze off a shot with a 223rem as it was running away. The shot was 150-175 yards if I remember right, and he said it went down immediately. He walked over to the coyote to find it laying on its side with its legs straight out and stiff... and it was looking at him. Apparently it's eyes followed him around and it was actively looking at him. He put it down with a 22lr handgun. They couldn't find an exit wound, or an entrance wound... they couldn't even find blood, what they did find was a patch of missing hair on the back of its head. His guess was that he hit it in the head as it ran and it hit hard enough to break something and paralyze it but the bullet was too fragile to penetrate. I had another instance where my brother and I were shooting prairie dogs, he spotted one and I ranged it at 106 yards, not a far shot for a 223. It was on top of the mound on all fours facing us, my brother shot and it was... gruesome. We went up to inspect the damage, I have a picture I could sure share, it was disintegrated down to it's shoulders but beyond that it was untouched. Granted the bullet could have veered off course and exited early but if it didn't we're talking 2-3 inches of penetration.

Don't get me wrong, I would rather have a bullet that expands too much than not enough, especially on prairie dogs. I was just trying to think of different ways I could change the characteristics of the bullet without changing the equipment. As much as I would love to add tools to my arsenal I'm not going to spend $100+ on a specialty tapered punch for drawing jackets just to 'see what happens' and find out it doesn't help the way I was hoping it would. Plus, being I'm trying to only use rimfire jackets if I wanted to change the jacket aspect of things I'd either have to buy copper jackets or get a set of copper tubing jacket maker dies and start from scratch. I've been able to sweep the floor at the indoor range after a rimfire competition a couple times so buying equipment to make jackets just seems like a waste. What I'm trying to get at is basically can you change the expansion characteristics while keeping the same jacket material/thickness and equipment. If I added a couple percent tin to some soft lead, would that cause the bullet to hold together better on impact or would it not matter because of the work softening?


I guess I should mention I have used clip-on wheel weight lead almost exclusively for cores, it's been really hard to get anything else to fill out such a narrow mold without getting wrinkles. Wrinkles hold lube which means the wrinkles stay there and the weights are inconsistent. I actually read the "swager's nightmare" thread yesterday and that did not look fun. Even though I use the harder lead I still have such a violent expansion, even with the 80gr .243" they just explode on impact. Is there any way I could keep them together just a little more by altering the lead alloy? Let's say I mixed clip-on and stick-on alloy 50/50, cast cores, swaged cores, seated cores, formed noses, then put them in an oven at 450* for an hour, took them out and let them air cool. That should bring the alloy back up to the original hardness that it was at when cast.

When you heat treat cast bullets it's beneficial to size before heat treating to go easier on you equipment but also to avoid the small amount of work softening on the driving bands, if that small amount of working is enough to cause issues then how much does fully working a core a couple of times do?

I do realize I'm extremely limited with my options because I want to stick with rimfire jackets, I'm just trying to start up a discussion about topic that doesn't seem to get covered a whole lot and learn something in the process.

Thanks guys!

[runfiverun]

re-heating to 450 letting them heat soak for a full hour and air cool will harden the alloy back to it's original BHN.
the full hour is necessary for the heat to penetrate all the way to the core of the material.
any further manipulation of the bullet [point forming] would need to be done quickly because you have a time window to work in while the lead is still soft.
it takes about 7-10 days for air cooled lead to realize it's full bhn again.
you could also water drop them from a 375* oven and realize about 18 bhn in the cores.

you could also try lowering your core weight and leaving a little hollow point so the jacket itself takes the brunt of the blow before the core starts to de-form this gives you time.
time is distance.

when I first started making 22 jacket 223 bullets I didn't have a way to swage cores for weight so I basically just made the cores [1 cavity core mold] then weight sorted them.
seated and point formed.
this left me with whatever weight I got in the different jackets.
so I erred on the lighter side to try and get them all to come out looking about the same.

I was getting the opposite of explosive.
the first yote I shot was loping away and I could see the poof of fur from the off side.
it turned on the after buners and run down the draw and out of sight but I knew I hit it.
[I thought I hit it]
Littlegirl was with me and seen the fur through her scope too so we walked down there and found some blood and the fur.
but the stupid thing run for about 500 yds before keeling over.
shooting ground squirrels was disappointing to say the least too.
they would just quiver up and tip over or get spun around on impact.

I started tapping a piece of #5 shot in the nose of them to fill in the void and that changed the whole outcome.
it was almost like shooting spsx hornady's versus their regular soft points in performance just by having that extra lead up in the nose.
even just packing old tumbling media in the nose made a difference in performance.

when I made a jig and started annealing just the forward third of the bullet after point forming and adding the piece of shot it was even more explosive.
this allowed me to slow things down and look for more accuracy while still getting the performance I wanted.

[Metroxfi]

Wow, that's crazy that you're getting results almost opposite of mine! What kind of lead do you use for your cores?

I'm wondering if you were having less expansion because you were going from cast to core seat with no extra working in between, whereas even though I use harder lead it gets worked more with the core swage process in there.

I keep my .224" bullets at or around 52-53gr so there is a small cavity in the nose, I didn't like the look of inconsistent noses with the little nub of lead here and there. With the .243" bullets I've been using 17HMR brass cut right at the base of the shoulder, I had a friend that wanted some 80gr bullets so I just kinda chose that length of jacket for simplicity and repeatability. The jackets are long for the 80gr though, as in the front 2/3rd's of the ogive is empty. I've shot a few handfuls of them and they are actually damn accurate and they also explode on prairie dogs. Does having that emptiness in the nose cushion the impact or make it fragment quicker? Would it act like a crumple zone in a car or since it's unsupported would it just get smashed and fragment? I shot a prairie dog at about 250yds with my 243 and it seemed like it unzipped him, folded him inside out, and zipped him back up. I've also shot them with 55gr fmj's and soft points in a 223 and it's like what you described, "just quiver up and tip over or get spun around on impact" hell I've even had them make it back down the hole. But with the 22LR shell 55gr they get turned into little gopher-skin rugs. I took my wife shooting once and she shot a bit low with one of the 55gr in a 223 and it hit the ground a couple feet in front of the prairie dog and you can actually see a spread of shrapnel hit the prairie dog and kick up dust all around it, it looked like the bullet just shattered. Come to think of it I don't think I've ever heard any of the rimfire jacketed bullets ricochet.

I had never thought of annealing the jacket again after forming it, I bet that makes it peel apart super easy. From everything you said I'm almost more confused, in your earlier post you mentioned that you use a soft lead core and it seems it takes a little bit of altering to get it to expand violently compared to me only using clip-on alloy and having crazy expansion even when they're put together as simply as possible. I wonder if that extra core swage is responsible or maybe something else. I made up a few hundred .243" for my dad the other day and I chamfered/deburred a jacket and measured (just with a dial caliper) and it came out .010" all around except one small spot that was .011", now that's with a cut down 17HMR and if I remember correctly the 22LR were .010"-.011" when drawn out. Is that about the norm for everyone else?

I have always wanted to try a .177" steel BB dropped in the jacket before nose forming and close the jacket up just enough to hold onto it. On impact the jacket would open quicker because its not closed down so tight and the steel BB would push down inside and initiate some crazy expansion. I've been too afraid to try it though, it seems like it would be too easy to push it to far up in the die and peen the die.

So back to the original question, would changing nothing but the lead alloy change my expansion characteristics? If I used stick-on alloy with tin added would it hold together better or still break apart just as easily due to the work softening? I know enough antimony can make alloys brittle, could that be why mine are so explosive compared to others made the same way? Does the content of the alloy even matter once its been worked so much, for example if one were to cast cores out of linotype (no, I haven't done this nor will I try) what would the BHN be once cast and air-cooled compared to core swaged? core swaged compared to core seated? Would linotype become dead soft from swaging? If you lose the hardness of the alloy due to work softening do you also lose its other attributes (ability of lead-tin alloys to hold together when expanding)?

I haven't played with it yet but I heard a secret for super frangible bullets. Apparently corn starch will turn into a hard plastic like material when put under huge amounts of pressure, then turns back into powder on impact. It'd make for super lightweight bullets but it wouldn't take more than a case full of trail boss to make them shatter, think of it as a poor man's powdered metal core.

[runfiverun]

antimony under pressure acts like a lubricant for lead if there is just antimony in the alloy.
the crystals break down under pressure and allow the lead to move and flow easier.
this is why they use antimonial lead in extruded lead products.
[pipe and window came]

tin has a different structure and resists bending and flexing you actually have to break the tin structure.
that's why you hear creaking and crackling when you bend or twist something made with high amounts of tin.

[Metroxfi]

So let's assume I have two alloys:

#1. pure lead with 5% tin for a BHN of about 10
#2. Wheel weight alloy, air cooled with a BHN of about 10-11

Even though the hardness of both alloys is very similar the molecular structure is very different.
If I were to make bullet cores for swaging out of both of those alloys would the chemical make up of the alloy effect the terminal performance of the bullet?

Would the differences in terminal performance be essentially non-existent due to the amount of work softening from the swaging process, essentially reducing the hardness of both alloys back to 5 BHN?

When work softened, would the alloys act the same even though they're comprised of different metals? Does breaking the grain structure of the different alloys cause them to act the same?


For example, when I cast hollow point handgun bullets, when I want the bullet to it a bit harder so I can push it faster and still hold together upon impact I add tin. However, when I cast the same bullet with clip-on wheel weights I get the same hardness as when I added tin but instead of holding together the bullet breaks into pieces upon impact. Do these differences carry over to swaged bullets, or are they cancelled out by the (sometimes) multiple go-rounds with being work softened?

[R.Ph. 380]

I just found a tire shop with a bucket of wheel weights. Knowing the amount of unusable steel/zinc/etc... what's a good price/pound to offer?

[Metroxfi]

A bit off topic but, assuming it's a full 5 gallon bucket (level with the top) they're generally about 50% lead. Most of the buckets I get are 100-120lbs so half of that would be 50-60lbs of usable lead, it just depends on how much you want to pay. In ingot form the lead may be worth about $1.00 per pound, in raw and dirty wheel weight form maybe $0.50 per pound. I stopped going to a few tire shops up here because the guys at the scrap yard were coming around and buying buckets of weights for $50 per bucket and they wanted me to pay that if I wanted the weights. Honestly, most shops out west just want a new empty bucket to replace the one I'm taking and I get them for free. I'd say if you took an empty bucket to trade (or even a sturdy cardboard box to dump them off in and leave their bucket with them) $25-$35 would be fair to both parties. keep in mind the steel and zinc are worth something, I save the steel until I have a few buckets of them and take them in for scrap, you could do the same with the zinc but be sure to keep them separated and be sure to tell the guys at the scrap yard what you do and that there is NO lead mixed in or they will be hesitant to take them.

Lets just say you gave them $50 for a bucket of weights with 50lbs of usable lead. Lets also assume that all you're going to cast is 200gr 45 SWC's. You'd get 35 bullets per pound, at 50lbs you're at 1,750 bullets. $50 for 1,750 bullets breaks down to about 2.9 cents a piece, beats the hell out of buying commercially cast bullets for 8-10 cents a piece. Just be sure to take a replacement bucket for them and be polite.

[Utah Shooter]

antimony under pressure acts like a lubricant for lead if there is just antimony in the alloy.
the crystals break down under pressure and allow the lead to move and flow easier.
this is why they use antimonial lead in extruded lead products.
[pipe and window came]


tin has a different structure and resists bending and flexing you actually have to break the tin structure.
that's why you hear creaking and crackling when you bend or twist something made with high amounts of tin.

Interesting. I did not know that. Aside from everything I have read here this intrigues me more than the rest. I have 2% antimony on a 50 lb spool that I purchased from Vulcan a while back. Sure I use it but have always been curious that the antimony makes the lead harder, perhaps causing damage to my dies.

I have read 1/2% before being used but thought perhaps 2% may be a bit hard. This came off the end of an order shipped to Hornady. Perhaps they are thinking your statements as well?

[runfiverun]

well those dead soft Hornady swaged target 38's contain 5% antimony.
I'd bet your roll was an order they made for jacket cores.

you'll see lots of range scrap stuff for sale it generally has a BHN of about 10.
a 10 bhn is about 2% antimony and maybe a whiff of tin is probably mixed in there from some commercial cast or from some different 22 brands.

[Forrest r]

Myself, I tend to use pure/soft lead for cores in rifle bullets and pistol bullets that I want to frag/implode.

For the velocities I run my rifle bullets at and what I use them for it didn't matter what alloy I used that was within the limits of my swaging dies. But then again I value accuracy over performance with the rifle bullets. I imagine using different alloys, jacket material/thickness, bonding would make huge differences in the performance of a rifle bullet.

Pistol bullets on the other hand I value performance over accuracy. There's huge differences in the alloy used for cores. Made up some extremely nasty hp's for the 45acp. Wanted the bullets to implode making a huge cavity but yet still have good penetration. I ended up using 7/8bhn alloy for the cores. The test target used to chronograph the test bullets that was taped to a bundle of tightly wrapped newspapers that was soaked for 24 hours along with the recovered bullets (I should say jackets).
[IMG][/IMG]

The bundle of wet newpaper that target pictured above was taped to. As you can see 2 bullets blew out the back of the bundle (holes in the blue picture). The other 3 jackets were recovered in the last 1" of the bundle.
[IMG][/IMG]

Did some testing with a hp bullet for the 44mag. Was looking for a bullet that would hold together in the 1100fps range. Why 1100fps??? To simulate a 100yd hit with a 1300fps load at the muzzle. Ended up using a 10bhn alloy to keep the bullets intact.
[IMG][/IMG]

[Metroxfi]

Myself, I tend to use pure/soft lead for cores in rifle bullets and pistol bullets that I want to frag/implode.

For the velocities I run my rifle bullets at and what I use them for it didn't matter what alloy I used that was within the limits of my swaging dies. But then again I value accuracy over performance with the rifle bullets. I imagine using different alloys, jacket material/thickness, bonding would make huge differences in the performance of a rifle bullet.

Pistol bullets on the other hand I value performance over accuracy. There's huge differences in the alloy used for cores. Made up some extremely nasty hp's for the 45acp. Wanted the bullets to implode making a huge cavity but yet still have good penetration. I ended up using 7/8bhn alloy for the cores. The test target used to chronograph the test bullets that was taped to a bundle of tightly wrapped newspapers that was soaked for 24 hours along with the recovered bullets (I should say jackets).
[IMG][/IMG]

The bundle of wet newpaper that target pictured above was taped to. As you can see 2 bullets blew out the back of the bundle (holes in the blue picture). The other 3 jackets were recovered in the last 1" of the bundle.
[IMG][/IMG]

Did some testing with a hp bullet for the 44mag. Was looking for a bullet that would hold together in the 1100fps range. Why 1100fps??? To simulate a 100yd hit with a 1300fps load at the muzzle. Ended up using a 10bhn alloy to keep the bullets intact.
[IMG][/IMG]

Ok that's great you were able to get things to work the way you wanted but what effects do the alloys of lead have on the performance? You mentioned that there are huge differences in the alloys used for cores but then only mention BHN's. What are the alloys? Are the BHN's measured after the cores are cast? after they're swaged? If you start with a cast core of 10BHN and work soften it with swaging does it matter how hard it started out? How much of a difference in performance between the 45acp and 44mag is due to the differences in amounts of notching, meplat size, and hollow point cavity depth? I don't think it's a fair comparison to say that softer lead makes the bullet more frangible then build the bullets entirely different from one another.

Runfiverun you mentioned that Hornady's swaged target 38's contain 5% antimony but also described them as 'dead soft' so does the content of the alloy have any effect on the internal or terminal ballistics of the projectile? I've never heard of a cast bullet with 5% antimony being described as 'dead soft' so obviously the swaging has an effect.

If your lead wire contains 2% antimony what exactly does that mean for the bullets you're going to make with the wire? The ingots used to make the wire were probably ~10BHN but have you measured the BHN of the wire itself? I would guess it's nowhere near 10BHN. If the wire starts out at 10BHN then gets extruded into wire and work softened, then bent around and straightened and cut and work softened some more, then swaged to weight and work softened again, then seated into a jacket and work softened yet again does the original hardness of the ingot carry over to the final product at all? Does the chemical make up of the original ingot have any effect on how the bullet will peel apart inside a target?

Does working the lead so much make the molecular structure irrelevant?

[Zbench]

Some things to add to the thread. At the shooting range we own and operate, we recycle 100% of the lead that is fired. The vast majority is jacketed bullets, with small amounts of 22 and shotgun mixed in. Every time I have ever had that corresponding melted lead assayed, it always comes back at 2% antimony. That tells me that commercial makers include some antimony in their bullets. We're not talking 5 or 6 buckets here, but like 40 tons a year on average. When you consider how small 22 bullets are and how scarce they have been over the past few years, it's hard to argue that the antimony present is from anything but what is in the cores of commercial bullets. I do not know the reason why, but clearly ammo makers put antimony in the cores for a reason.

Second, I extrude a lot of lead wire that I make from virgin, electrode grade ingot, 99.99% pure. I've tested it in the ingot form, in the cast billet form and in the resulting wire form, it's always 5 BHN. Metrofxi has indicated that "everyone knows that lead work softens" as you work it. It is news to me and is not consistent with the data I've collected. I use a commercial harness tester with a brinell ball to make a dent in the lead and measure the resulting circle with calipers. Since the force is known, and the size of the ball, hardness is directly determined by simple math. If there were any changes to the lead, I would see it as this technique is very sensitive. Are there any technical papers which describe this work softening phenomenon? Not being critical, just trying to learn something new if is in fact real and not a wives tale.

[Metroxfi]

Some things to add to the thread. At the shooting range we own and operate, we recycle 100% of the lead that is fired. The vast majority is jacketed bullets, with small amounts of 22 and shotgun mixed in. Every time I have ever had that corresponding melted lead assayed, it always comes back at 2% antimony. That tells me that commercial makers include some antimony in their bullets. We're not talking 5 or 6 buckets here, but like 40 tons a year on average. When you consider how small 22 bullets are and how scarce they have been over the past few years, it's hard to argue that the antimony present is from anything but what is in the cores of commercial bullets. I do not know the reason why, but clearly ammo makers put antimony in the cores for a reason.

Second, I extrude a lot of lead wire that I make from virgin, electrode grade ingot, 99.99% pure. I've tested it in the ingot form, in the cast billet form and in the resulting wire form, it's always 5 BHN. Metrofxi has indicated that "everyone knows that lead work softens" as you work it. It is news to me and is not consistent with the data I've collected. I use a commercial harness tester with a brinell ball to make a dent in the lead and measure the resulting circle with calipers. Since the force is known, and the size of the ball, hardness is directly determined by simple math. If there were any changes to the lead, I would see it as this technique is very sensitive. Are there any technical papers which describe this work softening phenomenon? Not being critical, just trying to learn something new if is in fact real and not a wives tale.

So you're saying the "data I've collected" about working lead is that pure electrode grade lead that is 5 BHN before extruding is still 5 BHN after extruding..? What about any other alloy? Have you only extruded 99.99% pure lead or have you extruded an actual Pb-Sn or Pb-Sb alloy? Have you ever measured the BHN of a cast bullet before sizing, then measured the driving bands after sizing? If you have a crystallized molecular structure that gets broken due to working then something is going to happen, if you don't have that structure to begin with then is moving things around going to effect anything?

One reference:

http://www.lasc.us/heattreat.htm

When most steel alloy's are either "worked" or "heat treated" they become both harder and more brittle, when lead is "worked" it becomes softer. Lead does not respond like steel, lead can be heat treated and made harder without adding any brittleness. Bullets destined for heat treating should be sized without lube and gas checked before they are heat treated, not after. Sizing hardened bullets is not only tough on your lubrisizer, tough on the bullets and tough on you, it also will work soften the driving bands of your bullets, the very part you wanted to strengthen. After a day or two for age hardening and to completely dry out they can be run through the lubri-sizer using a die .0005" to .001" larger than the die they were sized with.

A simple google search of "lead alloy fatigue" will net tech papers. Not to mention the various references to the phenomenon on this forum and others, I think even the lyman cast bullet handbooks make a note of it. Hell, take a clip on wheel weight and bend it so the ends are touching. Measure the hardness of the apex and the compare that to the unbent areas. I admit that work softening is not the norm in the world of metals but it does happen, it does depend on the amount of movement, type of alloy, temperature and many other things.

A second reference:

https://books.google.com/books?id=B5...soften&f=false

About lead-tin solder alloys in electronics, mostly concerning creep but does reference cyclic softening. The abstract on page 22 gives an overview.

[Zbench]

Metrofxi,

The post above speaks for itself. Talking about 5 BHN pure lead only. No matter what happens to it, it's always 5 BHN.

I'm not disputing that by adding stuff to lead and water dropping it you can make it harder. I once ran a group buy where I sold a special version of Lyman #2 with Arsenic added to make this effect even more pronounced.

I'm specifically asking about work softening. The paper you cited doesn't really support your case. The talks about some bullets he made that sat around for years and should have been age softened:

"We have all heard that heat treated bullet alloy will age soften over time but how much and how fast does this occur? While cleaning out the cabinet under my loading bench I came across a couple of box's of 35 caliber, RCBS 200 gr. heat treated bullet's properly labeled with the alloy (clip-on weights + 2% tin), the date and a BHN of 30. They were over 10 years old so I figured they would be putty by now but they tested at 26 BHN. 10 years, how is this possible? Taking from the "Key To Metals" article the antimony content of at least 4% and a low tin content controls the age strengthening and age softening of the alloy. It seems that if the percentage of tin had been higher or the percentage of antimony lower (or both) age softening would have been faster. With the box of heat treated bullets was a box of 7mm bullets of the same alloy and with the same date but not heat treated, the label said 11 BHN. In 10 years they also age softened and now test at 10"

So really hard lead doesn't soften at all when it sits around, but marginally hard lead softens by 10%? Seems like it could also be due to inaccuracy in measurement. Further, the author in that LASC article is talking about the grain structure of stuff sitting around changing over time, not lead or lead alloy that changes in hardness as it's being worked by mechanical means. I'm here to tell you that there is no harder mechanical manipulation to lead that taking a 3/4" lead billet and forcing it through a .185" hole under 2 tons of hydraulic pressure. By the phenomenon you are describing, the lead should measure much less hard than it started. It doesn't. It measures the same.

While I am talking about pure lead, I have extruded harder lead when I was experimenting with if I could do it. That lead also measured the same as before and after. I guess I'm just very skeptical that mechanical working of any lead alloy causes it to be softer.

Like I said, I'm trying to learn, but I still don't see anything that is compelling. Please someone point to an article that is science based. In my mind, this fits into the category, "I read it on the internet, so it must be true!"