Recipe help

[Frank]

I want to arrive at a BH of 28 + or - 1. I will water drop the boolits. I have the lead calculator at hand thanks to this great website So what final percentages of Pb, Sb & Sn on the calculator are optimal? By optimal I mean no more of each metal to achieve the result.

[lwknight]

Frank, I read a lot of folks get really hard cast by oven treating the bullets, even better than water dropping. I bet with only 6% SB and 2.5% Sn you could heat treat the bullets to your needed hardness.

[rob45]

The original monotype formula of 9Sn/19Sb/72Pb will be very close to providing the hardness you seek, but problems definitely await.

The primary problem you will have is the brittleness encountered with any alloy that has a high antimony content. Bullets made from such an alloy can be so brittle that they fracture upon chambering in the gun. Some use straight linotype (BHN 18-22, depending upon MANY variables) for the high pressure loads, but that is beginning to push the envelope of desired hardness vs. decent utility of the bullet.

Rather than trying to obtain the desired hardness strictly via alloy composition, my experience leads me to believe that one is better served by taking the common "rifle" alloys (2/6/92, 5/5/90, clip WW, etc.) and heat treating them. When using these alloys, simply water dropping will not get you the hardness you seek; you need to heat treat the bullets in an oven and then quench. Experimentation is definitely necessary for optimum results, but by doing so I have achieved over 30 BHN with clip WW.

Super-hard lead alloys (resulting from high percentages of antimony) are certainly in a league of their own. I have fractured such bullets by simply dropping them on the bench. I've had sizing dies do a number on them, too. As mentioned above, rough chambering can break one while closing the bolt. After being careful through the entire loading and handling process and finally actually getting some downrange, I then was able to shatter them against a steel target. Sort of makes me wonder how they would perform in a hunting situation, not that I would have to guess very hard. I suppose such bullets would make the ultimate varmint projectile! All of this was the result of an effort to avoid heat treating!

Bottom line: When trying to achieve BHN much past 20 or so, don't rely on alloy composition alone to do the job, and remember that water dropping probably isn't going to get you there, either. Take a reasonable alloy and heat treat the bullets. This is based upon my experience; your mileage may vary.

[montana_charlie]

I have the lead calculator at hand thanks to this great website.

If it's the same 'calculator' I have, all I can say is 'good luck'.
I can change inputs and see different results, but I can't trust any of it's 'solutions'.

Try five pounds of an 'alloy' that's 100% lead. Does it tell you that has a BHN of 8.6?
If the result for pure lead is that far off, how can anything else be right?

CM

[Frank]

I tried oven heat treating, but with only WW's. I thought a boolit coming out of the mold would be as hot as what I could practically do with heat treating. I tried 480'F in the oven and they slumped. Now I'm water dropping but adding alloy. I can only get to BH of 25. I need more for my application.

So what I'll do is go back to oven treat. 6%Sb and 2.5%Sn? Thanks alot for that suggestion, lwknight. I can plug those numbers in the calculator and see exactly what to add. And rob45, Thanks for those suggestions also.

So with those percentages, do you think 430'F in the oven for a 1/2hr to and 1 hr will put me at 27? I know the lasc page recommends higher temps, but now I'm mixing alloy. I'll give it a try.

[Frank]

Montana, I don't think it gives BH. But it helps me to quantify how much weight I need for each metal to get the percentages board members recommend. I can see the BH from the common chart that says "Lead - 5". Is there another calculator that gives you the BH? That would be neat, but don't think it's needed.

For example, in 6% Sb and 2.5% Sn it looks close to Lyman #2, that's BH 15. Now if I oven heat treat, will it go to 27-28? Looks good to me.

[lwknight]

Frank, I think you need copper jackets..With steel penetrators.

[lwknight]

All this hard boolit talk is making me want to cast for my 30-06. I don't see what good a super hard boolit is. Technology has done untold dollars research learning how to make high performance bullets.
I'm thinking to learn and experiment with paper patching. If I can actually cast soft boolits and shoot them at 3000 fps, That would be awesome.

I cast fot pistol plinking mostly because I shoot my rifle rarely and pistols/revolvers a LOT. So I have been using regular soft jacketed bullets to hunt with.

I totally see the romance in casting lead rifle boolits to shoot at realitively low velocities and casting for the old big bores but, super hard cast high power? Seems backwars to me.

[Frank]

The hard bullet seems to provide the best accuracy in my BFR 45-70. When I go softer, even with gas checks, groups open up. It likes copper also. I'll have to do a comparison.

[rob45]

The formula has been around longer than I can remember.

The 8.6 is not to be used as a reference to lead BHN, but rather as a constant in the formula. The constant is based upon the results obtained when the different elements are alloyed with lead.

I do not know which metallurgist came up with the formula, and he/she was probably some small-time genius working for some company that will never give the credit where it's actually due. Were one to calculate our commonly known bullet alloys using this formula, the results would be very close to what we already know.

The caveat to "playing with numbers" is the fact that we do not take into account the small variables which can sometimes make huge differences. Here are some points to consider:
1. How "accurate" are our hardness tests? Are we measuring true BHN as Johann Brinell did (known pressure on the test sample for a set amount of time giving a measurable indent, then calculating BHN with his formula), or are we using a "tester" which simply gives close (albeit slightly inaccurate) results? Likewise, what test standard did the originator of this formula use in testing hardness to prove the formula? Also of great consideration is when we test our sample, which leads us to the next point.
2. What materials are we using? Are we trying to prove the formula concerning ALL lead alloys? Anytime we're discussing lead, we might as well include the effects of arsenic. I cannot speak for the rest of the world, but most lead in the US comes from the mines in the midwest, and those concentrations of galena contain zinc, iron, arsenic, cadmium, and probably several other elements. I cannot think of (nor have I heard of) any process that completely eliminates arsenic from lead. Since we have long known the age-hardening effect that arsenic has in conjunction with antimony, it only makes sense to question the amount of time lapsed before testing for hardness in any antimonial alloy. Likewise, we have to inquire about the time lapse standards used by the originator to prove the above formula.

Using the above formula, here is how it stacks up to well-known industry standards:

Lyman No.2 (5/5/90) The formula calculates 14.65; the accepted hardness is 15.
Hardball (2/6/92) The formula calculates 14.70; the accepted hardness is 15.
20:1 (4.76%Sn) The formula calculates 9.98; the accepted hardness is 10.
30:1 (3.23%Sn) The formula calculates 9.54; the accepted hardness is 9.
40:1 (2.44%Sn) The formula calculates 9.31; the accepted hardness is 8.
Clip WW (.5/4/95.25) The formula calculates 12.43; the accepted hardness is 12.

We could go on with further examples, but I think these show us that the formula most definitely gets us "in the ballpark". The results will not be precise, but then again neither will our methods of alloying, nor our hardness testing, be precise.



Concerning heat treating, we can easily see that we might as well throw the formula out the window.

Any of the binary lead-tin alloys will not heat treat because there is no antimony present. For that matter, the bullet alloys containing no antimony tend to age-soften. Take a bullet of 20:1 and test it the day after casting; its hardness will measure very close to 10 BHN. Now test one a week later, and it will measure softer- closer to 9 BHN.

The ability to heat treat the alloys with antimony will depend upon not only how much antimony is present, but also how much tin is present. More antimony typically means a higher maximum hardness after heat treating. The more tin you have (in relation to antimony), the less maximum hardness you can achieve through heat treating. Compare WW (very little tin and @4%Sb) to Lyman No.2 (5/5/90). Even though the WW has less antimony than the No.2, you will be able to heat treat the WW harder because the No.2 has so much tin.

Look at hardball alloy (2/6/92) vs. No.2 (5/5/90). As cast, they yield nearly identical hardness. But try heat treating them and you will observe that the hardball alloy gets considerably harder. Once again, large amounts of tin in relation to antimony reduce our ability to achieve maximum hardness.

What about heat treating linotype (4/12/84)? Try it, and you'll be very disappointed with the time you just wasted.

So keep your ratios of tin and antimony in check when heat treating. BTW, I'm not degrading Lyman No.2 here. As a matter of fact I prefer it if I need a hard alloy for hunting, as it is considerably more ductile (tougher, less brittle, or any other of the 50,000 terms we use) than the hardball alloy. But if I needed an alloy that could heat treat to maximum hardness, it would not be No.2 That would be nothing more than an expensive experiment.


Frank mentioned not being able to get acceptable results when heat treating, so a few thoughts are in order.

1. The first consideration is the widely varying composition of WW. The accepted average is 4% antimony, but the past couple of decades have shown us that the weight manufacturers are not interested in precise composition, and the trend has definitely been in lower amounts of antimony or whatever they could obtain. So one batch may be able to heat treat above 30 BHN, while another (lower antimony) batch may not.
2. Consider the equipment (oven) being used to heat treat. Of primary consideration is the ability to maintain constant temp. Any oven that has a low-quality thermostat that constantly cycles the oven up and down will be more difficult to work with. This doesn't mean that acceptable results are only achievable with a true heat treating oven, it just means that experimentation (time) may be necessary to make the most of what you have. Some ovens show a tendency to get as much as 20 degrees above the set temp, then cut off and cool down the same amount before kicking back on. I call this cycling the "temperature window", and it will vary depending upon your particular oven.
3. Consider the quenching process after removing from the oven. Get those bullets from the hot atmosphere in the oven to the cold water as quickly as possible. The key to success seems to be how quickly the temperature changes. Sort of like the difference between searing a steak and boiling one. Frank, having the bullet solidify in the mold and then dropping in water is not the same as heat treating. The changes in the grain structure are different when you go from molten lead to a solid bullet to quick cooling. When you heat treat, the process is different because the metal is already solid, and it has been subjected to the elevated solid temp for some time before the quench.

As in any aspect of reloading, the most important consideration is to keep detailed notes of your efforts, and making small changes one at a time. Consistency is paramount; be sure every step of each "experiment" is the same as the last with the exception of that one minor change.

[Frank]

What about if the boolits are already water dropped? Can I heat treat them again in an oven? Or do I need to start all over, cast them, air cool, then oven HT?

[rob45]

What about if the boolits are already water dropped? Can I heat treat them again in an oven? Or do I need to start all over, cast them, air cool, then oven HT?

Even if the bullets are already water-dropped, you can still heat treat. The changes in the structure are similar to what takes place when hardening steel- heat it to a predetermined temp, and follow with a quench. Controlled temperature changes (heating/cooling) are how we control the structure and the resulting hardness.

When heat treating, the largest deviation from standard processing concerns the sizing and lubrication steps.

If you size your bullets, it needs to be done before heat treating. The bullets are so hard after heat treating that sizing is extremely difficult. In addition, we have to remember that lead work-softens. It does no good to heat treat the bullet, only to soften it by shoving it through a sizing die.

Naturally, sizing goes hand-in-hand with lubrication. You cannot have any lubricant on the bullets when heat treating in the oven. Different lubes have varying flash points, but they all smoke at the very least, and most will ignite. So much for consistent temperatures. I tried an experiment one time to see if the lubed bullets responded differently, and the net result was a visit from the fire department; the smoke was so thick the neighbor called them.

So we cannot have lube on the bullet, but sometimes we need something to ease the sizing process. Here's how I do it:

1. I start with clean, unlubed bullets. It doesn't matter if the bullets are already water-dropped, air-cooled, or even previously heat treated. Nor does it matter how old they are, as long as they are not lubed. If they are already lubed, I soak the bullets in solvent to remove the lube and then rinse in water to neutralize the solvent.
2. The sizing die is cleaned of any lubricant. The variances in alloy used, mold dimensions, and the sizing die will determine the ease of sizing. I try to size without lubricant first. Should that prove too difficult, I then use a cotton swab and lightly coat the inside of the die with dish soap. The soap does an excellent job of lubrication, while being easily rinsed off with water. Some people also use sizing lubricants to good effect; the most important factor is the ability to easily remove it. Nevertheless, if I can avoid using the soap as lubricant, it saves the step of having to rinse. It all depends on how much sizing is taking place, the amount of contact surface on the bullet, how smooth the die is, etc.
3. Heat treat and water quench the bullets. An entire article can be written on this step (and probably has). Be sure to keep detailed notes, especially noting the oven temp and alloy being treated. Also note the time lapse when testing for hardness, and be sure to use the same hardness testing equipment every time.
4. The bullets are now hardened, yet unlubed. We have to figure out a way to lube the bullet without sizing it again (remember that sizing will work-soften). Using tumble lube is one answer, as is pan lubing. If using an actual lubri-sizer, use an oversize die (.001 larger works for me) so that lubricant is being injected, but no sizing is taking place.

In conclusion, it's best to remember that wide temperature swings change the structure of the metal; that is why we are able to heat treat it regardless of its previous history. Just as important to remember is the fact that lead alloys work-soften, so any work (sizing) should be done before doing the final hardening process.

[Frank]

rob45, Great info. I'll go that route, size with the soap if needed and HT. And I'll take good notes.

[Frank]

OK, I took boolits that were 25, used dish soap to push them thru w/ GC's. Heated them 440'F one hour. This was 92Pb, 6Sb, 2Sn. Maybe less Sb and more Pb. The above spec depends on WW's being '12'. Maybe they're not. So I checked them after HT and they are only now '18' . Oh well, I'll wait a week and see, but maybe it's back to the pot with these suckers. Hard to believe it'll go from 18 to 27. I could have heated hotter, but I didn't want to exceed the melting point of tin 446'F. But you need to go to 480'F to get 30 BH. And that's only with WW's. Mine had more antimony. But maybe that doesn't matter. So if it's too soft, should I go to 480? Won't that make the tin melt?

[BABore]

MY straight WW's, sort of stick-ons, will WD or OHT to 28 bhn. I'm OHTing at 435F for an hour, then quenching. If my WW's were not producing such hardness, I would add about 10-25% of magnum lead shot. It will add a slight amount of antimony and alot more arsenic to the mix. I usually don't acheive full hardness til about a week old. Consistent hardness for accurate load development at about a month. Keeping the freshly hardened boolits at above 100-120F will decrease the wait time. Keeping them in the freezer will retard it.

[Frank]

I know what to do. I'll check them again and see if they're changing. If not then I'll go hotter.

[Frank]

OK, I tried 485'F and boolits slumped. So I lost 50% of them. After 20 minutes I dumped them in the water. So now I have 35 GC'd boolits of unknown hardness. Oh well, back to the pot for the rest. I don't get that lasc site, talking about 485'F heat treating. I used a Taylor thermometer. I'll have to go the alloy method to get what I want. Get some Magnum shot like BaBore suggested. In the meantime, I've got some condom bullets to shoot in the meantime. That's the way the cookie crumbles sometimes.

[lwknight]

Boolits will heat treat at 425 and some venture as far as 450 to get the max out of it.

[fredj338]

OK, I took boolits that were 25, used dish soap to push them thru w/ GC's. Heated them 440'F one hour. This was 92Pb, 6Sb, 2Sn. Maybe less Sb and more Pb. The above spec depends on WW's being '12'. Maybe they're not. So I checked them after HT and they are only now '18' . Oh well, I'll wait a week and see, but maybe it's back to the pot with these suckers. Hard to believe it'll go from 18 to 27. I could have heated hotter, but I didn't want to exceed the melting point of tin 446'F. But you need to go to 480'F to get 30 BH. And that's only with WW's. Mine had more antimony. But maybe that doesn't matter. So if it's too soft, should I go to 480? Won't that make the tin melt?

I understand you need at least a week to gain full BHN from heat treated bullets. Wait at least that long before trying to cahnge anything in your alloy or technique. I assume you have been here. http://www.lasc.us/HeatTreat.htm

[Frank]

Yes, I was there. It says 485'F. I couldn't resist. Had to try it. Next time I'll do what BaBore said to do.

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