Is there an advantage to this?

[Lead melter]

Suppose I take an alloy of 50/50 WW/pure, mold some boolits, water quench in iced water, then wake a few weeks for them to completely harden. From what I have read here, the boolits will have a hard "shell" while the innards would still be relatively soft.

Now if I decide to heat treat them in an oven, would the process result in a completely hard boolit, or would the inner boolit harden and the outer shell get even harder? It seems as though the latter case would be the best option, at least in my mind.

The reason I ask is that from time to time I may have the need of a harder boolit than quenching produces. Sure, it's simple enough to cast more from a harder alloy, but why do that if I have several boolits of the particular design, but just want to try some that might be harder?

BTW, I have never oven treated a boolit, so this is all new territory to me.

Opinions count.

[44man]

First, you don't need ice water, just cold from the tap.
The surface will be harder because the lead in the center cools slower. The mix of 50-50 is good because it will be hard enough for the rifling yet is still ductile.
I just did my first oven hardening because a very good man from here sent me some trial boolits that were air cooled. I went to Wall Mart and bought a small stainless strainer, the one for spaghetti, put a bunch of boolits in it and stuck it in the oven for an hour at 435*, then quenched them. Worked like a charm.
But they will be the same as water dropped in the end although more even.
Water dropping or heat treating does make the whole boolit a little harder but in the end it is the alloy itself that hardens the entire boolit more but it still takes aging time. Boolits with antimony will also grow in size as they age so you should not measure or test for hardness until they age long enough and that time varies with the alloy.
You can cuss at your mold if you measure right out of the mold only to find it grew .001" or even .002", depending on the caliber, after it sits a week.
Air cooled also harden according to the alloy but they lack the harder surface.
If anything here is wrong, please correct me! :Fire:

[Calamity Jake]

Suppose I take an alloy of 50/50 WW/pure, mold some boolits, water quench in iced water, then wake a few weeks for them to completely harden. From what I have read here, the boolits will have a hard "shell" while the innards would still be relatively soft."


The above is true, hard shell, soft center. When sized the hard shell will become a little softer but not as soft as the center. Lead alloys work soften where other metals work harden.


"Now if I decide to heat treat them in an oven, would the process result in a completely hard boolit, or would the inner boolit harden and the outer shell get even harder? It seems as though the latter case would be the best option, at least in my mind."


No, The inner part of the boolet is never cooled fast enough to get hard, it will always be softer then the ouside. Lead alloys can only get so hard when heat treated, water droped or oven heat treated will be about the same for a given alloy, although IMO the oven heat treated boolets will be more uniform from one boolet to the next because they are all quinched at the same time.
When water droping, if one or more boolets hang up in the mold when opened then the last to hit the water will be somewhat softer than the first because the alloy temp is different from boolet to boolet but, the difference in hardness may not be enough to make a difference.
Also as the casting/water droping session progresses the water becomes warmer so the quinching process is different.



"The reason I ask is that from time to time I may have the need of a harder boolit than quenching produces. Sure, it's simple enough to cast more from a harder alloy, but why do that if I have several boolits of the particular design, but just want to try some that might be harder?"

50/50 L/WW will only get so hard when HT'ed, change the ratio toward the ww and it gets harder, straight WW will be harder still, add a little antimony(2-3%) and it's gets harder than the WW alone.
Lino/Mono heat treated will be the hardest lead alloy that you can get.

BTW, I have never oven treated a boolit, so this is all new territory to me.

Opinions count.


If you want to maintain a good hardness then apply gas checks(if needed) and size first, then oven HT.

I oven HT'ed about 400 22's last Monday evening for my AR.

You need a good oven thermometer to find the right dial setting for 425°
Place checked and sized boolets in some kind of small screen flat bottom wire basket, put boolets in basket and place in oven for one hour @ 425°, at which time remove basket and quickly dunk basket and all in ice water until cool(1 to 5 minutes) depending on caliber, the boolets will be at there the full hardness in 24-36 hours.

[leftiye]

Sizing produces a layer of dead soft lead on the surface of the boolit. This includes the metal that was smooshed when sized, and somewhat more that was affected. For best results size then heat treat so as to reharden this layer (remember this is what takes the rifling).

1/2 % tin and 5% antimony lead hardens the best - BHN42! (from Harrison's book "Cast Bullets", verified by personal experience). More tin interferes with hardening.

[454PB]

Boolits quenched from the hot mould do not "surface harden". I've filed away enough area to be 1/3 of the diameter into the boolit, and it tests the same hardness as the surface. I can't say it's the same hardness all the way through, but it's certainly not only hard on the surface.

Heat treating is more uniform since the temperature change is more uniform. You can pull a tray of oven heat treated boolits from the oven and dump them in a bucket of water within maybe 5 seconds. Now compare that to knocking them loose from a two to four cavity mould and having all of them hit the water at the same time/ temperature. In addition, each dump from the mould to the water increases the water temperature.

[Bret4207]

Okay- I have problem with all this. Since lead alloys work soften and every tool we use to cut the heat treated boolit functions to do just that, soften the boolit, then how do we know the center is so much softer? In theory, yes I agree. But had anyone come up with a for sure answer or are we stuck at theory?

BTW- All WW alloys, HT'd or not and mixed with whatever, are ductile to an extent. Until we get into the fresh Linotypes and Monotypes and heat treating them we're not going to get "brittle" boolits. Also remember that the velocity they hit the target at and the hardness of the target itself determine much of the "brittleness". I've fired boolits over 30 Bhn into sandbanks at near 2000fps and they mushroom like Remington Corelokt ad. IOW, IMO "brittle" boolits aren't a certain thing just because they're Linotype HT'd to 35+ Bhn

[44man]

Okay- I have problem with all this. Since lead alloys work soften and every tool we use to cut the heat treated boolit functions to do just that, soften the boolit, then how do we know the center is so much softer? In theory, yes I agree. But had anyone come up with a for sure answer or are we stuck at theory?

BTW- All WW alloys, HT'd or not and mixed with whatever, are ductile to an extent. Until we get into the fresh Linotypes and Monotypes and heat treating them we're not going to get "brittle" boolits. Also remember that the velocity they hit the target at and the hardness of the target itself determine much of the "brittleness". I've fired boolits over 30 Bhn into sandbanks at near 2000fps and they mushroom like Remington Corelokt ad. IOW, IMO "brittle" boolits aren't a certain thing just because they're Linotype HT'd to 35+ Bhn
I agree, you can't do anything to a boolit and then get a proper reading, even sizing after hardening will take away any surface hardness. Personally, I only want to harden a softer alloy like 50-50 so it shoots OK. I never have a problem with WW or harder if air cooled, or dropped in water. No leading or loss of accuracy.
Now what a boolit does in game is a different story and the faster a boolit is shot, the softer it has to be or it just punches a hole. Never depend on hardened WW metal to expand.
I have lost 2 deer shot with my 45-70 BFR with hard WFN boolits shot too fast. The ones I did recover went too far and showed little internal damage.
We shot WW boolits through 40" of soaked phone books and paper, through 16" of hardwood and through many, many deer. The nose does not deform. However, shot through 2 layers of steel belted tires and impacting a steel plate, they turn to dust.
Her are some boolits shot through 40" of wet paper, 16" of oak or dug out of dirt after going through a deer. These are all water dropped WW boolits. If anyone thinks their boolits will expand in a deer, look at them closely again! [smilie=1:

[44man]

All of those boolits just ruin the insides of animals if the velocity is kept below 1400 fps. Go faster and the pressure wave in front of the nose moves tissue out of the way so the primary wound channel is very small. What you will get is a large secondary channel that collapses. Lungs only have a small hole through them.
Hit a bone or very tough muscle to slow the boolit, then the nose will work and make mush out of lungs.
The best thing to do is to tailor the alloy for the velocity so some expansion will slow the boolit so it can do work inside the animal. The pressure wave has to be reduced.
Muzzle energy or high velocity has never killed anything, only the work a boolit does when inside them will do the job.
With a very hard boolit, slower is better with a large meplat.

[waksupi]

If you are shooting deer with a .45-70 and they are not dieing, you aren't hitting them where they need to be shot. Period.
I have used cast boolits up to 2460 fps for hunting, and when the animal is shot where they are supposed to be shot, they die. End of story.

[BABore]

Suppose I take an alloy of 50/50 WW/pure, mold some boolits, water quench in iced water, then wake a few weeks for them to completely harden. From what I have read here, the boolits will have a hard "shell" while the innards would still be relatively soft.

Now if I decide to heat treat them in an oven, would the process result in a completely hard boolit, or would the inner boolit harden and the outer shell get even harder? It seems as though the latter case would be the best option, at least in my mind.

The reason I ask is that from time to time I may have the need of a harder boolit than quenching produces. Sure, it's simple enough to cast more from a harder alloy, but why do that if I have several boolits of the particular design, but just want to try some that might be harder?

BTW, I have never oven treated a boolit, so this is all new territory to me.

Opinions count.


To directly answer your question, yes you can control the depth of hardness to a certain degree. It's much easier to do on big 458 boolits than little 30 caliber ones. There is a minimum temperature required for the alloy to heat treat. Go below that critical temp. and not too much happens. Go too high on the temp. and your boolits slump over. For 50/50 WW-Pb, I've found that 435 F is just above the temp. needed to heat treat it to 22 bhn. If I OHT it at 450 to 475 F, it still comes out at 22 bhn. So what's the difference. If the entire boolit is at the minumum critical temperature, the outside is immediately quenched and hardened. The inside of the boolit drops below the critical temp. before the rapid quench is brought to bear on it. I have tested this process by comparing expansion in a common media. The same can be done with straight WW's too, but it is harder to see the expansion differences as WW's are a little more brittle and don't hold their expansion (mushroom) as nice. If you don't want to go the soft core route, you can also OHT WW's to there max hardness. Then you can oven anneal them down to the hardness desired. I ran batches in 25 F increments to determine a temp/hardness scale. I was able to go from a full hardness of 28 bhn, down to 16 bhn, in about 2 bhn steps. This was with WW's only. Didn't pursue it much after my study cause I found the 50/50 alloy did everything I needed. I now get fancy with hollow pointing, annealing the nose of HT'd boolits, or combining the two.

[454PB]

In my opinion, filing into the side of a heat treated boolit is not the same thing as sizing that same boolit in regard to "work softening". But as long as we're discussing the fact that sizing resoftens a HT'd boolit, what happens when it's seated into a case and fits so tightly that you can see the lube grooves? Is that enough "work softening" to reduce it's suface hardening?

[leftiye]

I'd expect so. Further, if you stick a boolit in a case and the case sizes it down, or if the boolit is sized down by your crimp, same result. As cast boolits tend to not ever live up to what you'd expect for a given hardness, it is worthwhile to err on the side of not deforming any given boolit.

[44man]

In my opinion, filing into the side of a heat treated boolit is not the same thing as sizing that same boolit in regard to "work softening". But as long as we're discussing the fact that sizing resoftens a HT'd boolit, what happens when it's seated into a case and fits so tightly that you can see the lube grooves? Is that enough "work softening" to reduce it's suface hardening?
Might be true but as long as the part of the boolit that engages the rifling is still hard enough, the loss of any skin hardness doesn't matter. I never paid any attention to the surface and size boolits I cast a year ago. As long as they are 18 to 22 BHN I am happy.
They need to be hard enough to resist sizing when seating. Even if the hard skin was retained, it goes away in the trip through the throat anyway.
I don't think sizing a little will change anything and the surface will only get as soft as the alloy will allow anyway, you can't turn it into pure lead. So what if .0002" is softer then what is under it?

[44man]

If you are shooting deer with a .45-70 and they are not dieing, you aren't hitting them where they need to be shot. Period.
I have used cast boolits up to 2460 fps for hunting, and when the animal is shot where they are supposed to be shot, they die. End of story.
Well if a double lung hit right behind the shoulder is wrong, I guess the 366 deer I have killed should not have died! :mrgreen: I gut all my own deer and do a necropsy on every one, I also butcher all my own. I pay close attention to what a boolit, bullet or arrow does. Funny that a round ball from a muzzle loader is so deadly! :drinks:
Now remember we are talking revolvers here. I have no idea what my boolit will do at rifle velocity. They might very well expand and work. I can't answer that because I never shot a deer with a hard WLN or WFN with a rifle. I gave up hunting with rifles, too easy!
So is there a velocity range where the hard big meplat boolit is perfect but does not work from about 1400 fps to some other velocity and then starts to work again when velocity is increased farther? I have no idea. :confused:
You have not answered that question either.
I can show you what a hard WFN does at 1329 fps.

[Bret4207]

In my opinion, filing into the side of a heat treated boolit is not the same thing as sizing that same boolit in regard to "work softening". But as long as we're discussing the fact that sizing resoftens a HT'd boolit, what happens when it's seated into a case and fits so tightly that you can see the lube grooves? Is that enough "work softening" to reduce it's suface hardening?

That's where my problem comes in- we're not all talking about the same thing, we're talking generalities at best. I suppose what we need is a metallurgist or acces to a text book of some sort to figure this out.

[44man]

That's where my problem comes in- we're not all talking about the same thing, we're talking generalities at best. I suppose what we need is a metallurgist or acces to a text book of some sort to figure this out.
I have learned to relax and quit nit picking about all of that stuff. If the boolit resists sizing when seated it will be accurate. I can size and lube boolits right away, let them age a week and mix them with boolits a year old before lubing. Then shoot a 1" group at 100 yd's with my revolver. I have rounds loaded 10 years ago that shoot the same. C'mon guys, just make the boolit the right hardness to start with and the right size.
If you heat treat 50-50, water drop WW or a harder alloy, they will all work. If you size after casting and let them age, they shoot the same as boolits stored a few years and then sized and lubed.
Not a single one of you can dispute the revolver accuracy I get!
All that is needed is to tailor the INTERIOR hardness of a boolit to work on whatever game you hunt as long as the surface resists sizing and takes the rifling, all is good.
Don't sweat the small stuff, how you load your rounds is more important. Brass is more important. The gun itself is more important.
If I had to worry about a hard skin on a boolit, I would buy jacketed bullets. :Fire: