Heat treating cast bullets.

[Smoky Mountain Red]

What is the hardest you have ever been able to get a cast bullet?

What is your method of choice?

-Red

[The Cast Bullet Kid]

Not sure of the Brinell but after 1/2 hour in the oven at 230C and a bath in cold water they are like "the hobs of Hell".

[BCB]

I have gotten bullets to a BHN of 32 when a proper alloy was used to cast the bullets.  I put my bullets in a cold oven and set the temperature to 450°F and let them in there for 45 minutes.  Then they hit the ice water.  Good-luck...BCB

[Smoky Mountain Red]

BCB,

What was the alloy you achieved the 32 Bhn with?

I have been experimenting with several different combinations and have been only coming up with about 22 average. I'm thinking my wheel weights are the source of the inconsistency. I have gone to a much larger batch and am awaiting my lead hardness tester.

Also what do you guys recommend for the hardness tester?

SM Red

[BCB]

Smoky Mountain Red,
I use an alloy of 2-1 (Lyman #2-WW).  I put about 10 pound of this in my furnace and add approximately 1/4 cup (volume NOT weight) of hard magnum shot.  This adds a bit extra of antimony and arsenic.  It is certainly the added shot that caused the hardness in my opinion.
I have a SAECO tester.  They can be a bit difficult to use, but I find the repeatability of them to be exceptional.  They need a meplat that is wide enough to allow the needle to penetrate the alloy.  If I am checking anything but wide meplat handgun bullets (round nose, spitzers, etc), I cut several of the bullets in half after they have been cast.  I then heat treat these right with the good ones and that gives me a bullet with an acceptable meplat for the SAECO tester.  Good-luck...BCB

[quigleysharps4570]

I'll 2nd that SAECO vote.

[HL]

I will normally stay between 30-35 BHN, using straight WW metal, heated at 450degrees for 1 hour and then quenching in ice water. Full hardness was measured 24 hours after quenching.

From what Veral's book states, if I remember correctly, you need to set a few bullets in the oven and continue raising the temp in 15 degree increments, until the bullets slump when the pan in tapped. Then back off the temperature 15 degrees and this is where you will get the optimum heat treating for the alloy.

[Shoot!]

My main problem with heat-treating wheelweight alloy to 30+ BHN is that they age-soften to the low 20s over the course of several months, and any loads initially worked up will change over time as they soften,  screwing up accuracy and potentially raising pressures dangerously high. I have been told that if they're heat-treated to 21-22 BHN, they will stay at that BHN indefinately (that's what BTB does), but I've never seen a temperature/hardness curve. This would give linotype-like hardness without the brittleness/expense the antimony provides.
Does anybody what temperature/time recipe will bring about a 22 BHN for wheelweights? Or do I have to wait a year before the age-softening stops and good loads can be worked up?

[Longcruise]

My main problem with heat-treating wheelweight alloy to 30+ BHN is that they age-soften to the low 20s over

I think the softening will go alittle slower than that.  Storing them in the freezer will slow them up a bunch but don't put them in till they have had a couple days to reach full hardness.

I have been told that if they're heat-treated to 21-22 BHN, they will stay at that BHN indefinately

I think they will continue to soften right on down to about 10 to 14 bhn eventually.

[Smoky Mountain Red]

This is odd.

The people I bought the equipment from said the opposite. I won't mention the person's name, but I was told that after casting bullets they will harden up a bit on their own...?

Now I'm wondering if that means they will go from dead soft to slightly hard on their own or was this person just incorrect.

I would like to understand what process is taking place to soften up the bullets after they sit for a while. Possible oxidation or migration  of some sort? Maybe someone out there has a bit more insight.

I have noticed that some of my favorite .357 swc's left more lead a few years later when I got around to shooting them again.

I've heard about using the ice water and dropping them right out of the mold. Tried it once... drops of water splashed into the pot and I stopped that right quick! Still missing hair in some places... :-)

I'm going to try adding that hard shot.

Does the Saeco read directly out in Bhn or do I have to cross it over?

Thanks,

SMR

[quigleysharps4570]

I've heard about using the ice water and dropping them right out of the mold. Tried it once... drops of water splashed into the pot and I stopped that right quick! Still missing hair in some places... :-

Does the Saeco read directly out in Bhn or do I have to cross it over?

Thanks,

SMR

I keep my 5 gallon bucket of water several feet away and turn with my back towards the pot when I drop the bullet in. The SAECO has a chart with it that shows SAECO and Brinell Hardness. Real simple.

[HL]

Partially true,

If you leave the heat treated bullets out in the open, room temp., over the course of a year, they will approaceh 22BHN, but will not drop below that.

I store mine in a freezer at 0 degrees and after 2 years have not lost any hardness from what I first heat treat for.

Going from 30-35 BHN to 22BHN should not raise pressure enough to worry about, in my opinion. I have shot the same bullets with both BHN hardness and have noticed no difference. Not that there may be some scientifically measurable difference, but as far as accuracy, velocity, or case appearance, there was no difference.

[Shoot!]

HL, thanks for verifying that the age-softening stops at around 22 BHN.

[Smoky Mountain Red]

Great information!

What kind of Bhn could I expect by dropping them into the ice water straight from the mold?

Would they need any additional hardening?

Hope I don't sound like a broken record. I'm trying to produce the best bullet I possibly can.

Now for phase II...

Has anyone heard about removing lead from a barrel with a
peroxide and ammonia mix?

I have been told that it is good for lead removal and it won't affect the finish on a gun barrel.

SMR

[jgalar]

Someone posted this web page, it has good info on casting...

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

[R.M.]

Red
You say "I'm trying to produce the best bullet I possibly can."
Making a bullet harder doesn't necessarily mean it's better. In some cases, softer is better, it depends on the application.

Good luck in your quest.
R.M.

[Longcruise]

This is odd.

The people I bought the equipment from said the opposite. I won't mention the person's name, but I was told that after casting bullets they will harden up a bit on their own...?

They may have been refering to the cast WW bullets that are not heat treated.  If you drop ww bullets from the mold and leave them sit at room temp they will harden up slightly over a period of about two weeks.  They will end up around 10 to 13 BHN, having started at around 7 or 8 BHN.

If you leave the heat treated bullets out in the open, room temp., over the course of a year, they will approaceh 22BHN, but will not drop below that.

Not sure what you are saying there.  Are you saying that over a year they will hit 22 and never drop below that?  I don't have a Brinnel tester but it seems to me that they would eventually come down to the 12 to 14 range, that being a sort of point of equilibrium for WW.

A ggod question to ask in Veral's forum!

[HL]

I first read about the heat treated bullets not dropping below 22BHN after being heat treated to 30-35BHN, as stated above in Veral's book "Jacketed Performance with Cast Bullets".

I just left some bullets I cast sitting around my reloading bench for a couple of years after casting and heat treating and decided to see if that was true.

I put the bullets in the hardness tester and the BHN was right around 22-23. So, I'm not too concerned about high pressure using the same loads.

Good Shooting,

HL

[Longcruise]

I put the bullets in the hardness tester and the BHN was right around 22-23. So, I'm not too concerned about high pressure using the same loads.

I would agree on the pressure thing.  I have Veral's book but don't recall that section of it.  Good time to review it I guess.

Thanks

[Smoky Mountain Red]

RM,

Can you give me an example of when a soft bullet is better for an application?

Let me also ask this, is it worth the extra effort to get bullets up to 30+ bhn if they will settle around 22 anyway? Will 22 be sufficient for most applications?

Another point to ponder...
should the same lube be used for all bhn ranges? eg. If you have a softer bullet should the softer lube be used to better serve the following bullet as it enters and conforms to the barrel?

??

SMR

[Sixgun]

Smokey,

Maybe I can help with the question on what applications are good for a softer bullet.

Let me start off with Hard Bullets.  Most of the time in a hunting situation, a hard bullet with a wide flat nose is desirable.  It will transfer allot of knock down power on the initial contact.  It will also penetrate in a straight line.  Think of it like dropping a big flat rock into a pool of water, it really makes a big splash.  

Paco Kelley makes an expanding bullet by water dropping bullets to get them hard.  Then he sits the bullet on its base in water with the nose sticking out of the water. He then uses a torch to heat up the nose which he lets cool off slowely.  This gives an expanding nose which stops expanding when the expansion reaches the hard part of the bullet.

If you are shooting targets, like steel silhouette targets, or steel plates, that you don't want to damage, a soft bullet works great.  I cast my soft bullets out of lead cleaned from our indoor range bullet traps.  It is mostly 22 lead and is pretty soft.  I use a fast powder like Bullseye or Win 231 on these bullets and get excellent accuracy with them and they do not damage the targets.  On most silhouette ranges, if you damage targets, you will be asked to stop shooting.  Soft bullets and fast powders allow good obturation with low velocity.  This combination will usually allow the best accuracy that can be achieved with most cast bullet situations.

I hope I didn't confuse anyone here and I also hope this will help.

Sixgun

[Smoky Mountain Red]

Sixgun,

That really makes sense. If a person wants a soft nose bullet then the bhn can be adjusted to match the need. So if I produce bullets that are roughly 22 bhn to start, then they can be softened up and if they need to be harder they can be heat treated at that time. I'm trying to avoid any unnecessary work. From what I am hearing it sounds like heat treating is a moot point after so long anyway.

Does anyone know if a bullet can be re-hardened once it has softened up?

Thanks for the great input everyone!

SM Red

[harley45]

Smokey,


 

Paco Kelley makes an expanding bullet by water dropping bullets to get them hard.  Then he sits the bullet on its base in water with the nose sticking out of the water. He then uses a torch to heat up the nose which he lets cool off slowely.  This gives an expanding nose which stops expanding when the expansion reaches the hard part of the bullet.

Sixgun would you have anymore information on this technique? It sounds interesting to me.
Thanks

[Longcruise]

So if I produce bullets that are roughly 22 bhn to start, then they can be softened up and if they need to be harder they can be heat treated at that time.

Your not going to get bullets of 22 bhn of wheel weights without heat treating them!

You could heat treat them and wait a year, or maybe even two years, for them to degrade to 22bhn but that doesn't seem too practical :-)

The question of how to heat treat to a 22 bhn would seem to be the answer to your quest.  I guess one could conclude that oven heat treating at various temps and the water quenching will provide different bhn ratings.  I don't know where  you would find a scale that would give you the bhn ranges for various heat treating temps though.  If you have a bhn tester you could create your own scale.

OTOH, I don't recall you mentioning what caliber an muzzle velocity you plan to shoot at or what you will shoot it at.  The hardest bullet possible is not always the best for every application.  Do you want a hunting bullet?  A match bullet?  a plinker?

BCB explained how to get wheel weights to their max hardness and if you are worried about them degrading, then just shoot faster :grin:

For most uses, plain old air cooled wheel weights cured for two weeks at room temp will work just fine for many applications including hunting up to 2100 or 2200 fps.

[Smoky Mountain Red]

Point well made!

I will try the trick about adding the hard shot and water quenching. Do you shoot a bullet that fast without a gas check?

I was told a rule of thumb was over 1800=GC...

Thanks.

SM Red :?

[Longcruise]

I will try the trick about adding the hard shot and water quenching. Do you shoot a bullet that fast without a gas check?

No need to add the hard shot, the wheel weight mixture will harden nicely without wasting expensive shot.  The last batch I heat treated I soaked in the oven for 1 hour at 350 deg and then plopped them into a cold sink full of water.  I have no idea what bhn they hit but they are harder than plain wheel weiht bullets from the same batch of lead and the same mold.  You can take a few of the untreated bullets in one hand and the treated bullets in the other and shake them.  You'll notice that the hardened ones clink a little louder and have a sort of a ring to them.  Even after water quenching the don't hit full hardness for a couple days after.

You can test comparative hardness by cutting two bullets off at the same point (not needed with fat flat nose pistol bullets) and then place them base to base and squeeze them in a vice.  softer bullet squasshes more :grin:   Ain't that scientific?

I don't go much over 1500 fps with a plain base bullet and use gas check designs for anything faster.  I've got one .44 cal slug that weighs in at 320 grains and takes a gas check.  A revolver will push it just over 1300 fps and probably the gas check is unncecessary but thought I might shoot it faster out of a rifle someday but never have.  Don't even own a .44 any more!

[cbrick]

Interesting thread. I hope the testing I have done over the past several years helps answer some the questions.

Wheel weight heat treated to any achievable hardness will slowly soften over time. The harder they are made, the faster they will age soften. Keeping them in the freezer will all but stop the softening. The warmer they are kept after heat treating (like on the dash board in August) the faster they will soften. Non-heat treated WW will age harden over several days (only a couple of BHN). The hardest I've ever gotten water quenched bullets is about 17 and normally they are inconsistent ranging from 14 to 17 BHN.

I have done a lot of testing of BHN's and heat treating at different temps. An oven that holds a very steady, consistent and repeatable temp is needed to get repeatable results.

The alloy is WW + 3% tin

485 degrees . . . 30 BHN in 48 hours
460 degrees . . . 25 BHN in 48 hours
430 degrees . . . 20 BHN in 48 hours
415 degrees . . . 18 BHN in 48 hours
400 degrees . . . 15 BHN but further hardened to 16-17 BHN in 2 weeks.

Adding shot to WW will not add any ability to heat treat though you are adding a bit of antimony. Wheel weights already have plenty of arsenic and adding more will do nothing. The antimony will add a little hardness but also brittleness.

"Does anyone know if a bullet can be re-hardened once it has softened up?"

Yes, if you have heat treated bullets to say 28 BHN and later you want them 20 BHN, simply re-heat them at 430 degrees and dunk em in cold water. If you have heat treated bullets at 15 BHN and later you want 20 BHN, just re-heat treat them.

Harder cast bullets will cost you in fps. I have a Freedom Arms 357 load that shoots 28 BHN bullets 60 fps slower than the same load using 20 BHN bullets. The softer bullet also groups a little better though neither bullet leads the bore with this load.

Harder is not always better. If the bullet is too hard to obturate, gas cutting usually occurs on the base band on the non-driving side of the rifling and barrel leading is likely.

I stopped experimenting with lube when I started using LBT Blue. I have not had any lube related problems since I started using it. I use it for 45 ACP loads under 700 fps and the hottest magnum loads and I have used it in a 308 Win XP-100 at 2500 fps. I just order more from Veral and get on with my life.

Rick

[Lloyd Smale]

Biggest problem with cast bullets both commercial and home made is that people are making them to hard! There is absoultely no reason to use a bullet that is harder then 18 bh in any handgun load. Most handguns are fine with 12bh or regular wws. If your leading at 18 bh in a handgun more hardness isnt going to help anything. You either have a bad forcing cone or barrel or alignment problem. Like was stated in a previous post your bullets have to bump up into your bore to seal the gasses from leaking by your bullet. Ive seen just as much leading problems for to hard of a bullet as from to soft. Im not one for water dropping bullets. It is just about impossible to keep bullets at the same temp dropping them out of a mold hand casting to get consistant hardness and oven tempering is to time consuming. There is no advantage in my opinion to a bullet over 20 bh in any gun with a good barrel and i can get that with lynotype. Weve dont alot of penetration testing and the best alloy weve found at mag handgun velocites is 5050 ww lyno and that gives about 17-18 bh its hard enough to keep from riviting and ductable enough to keep from fracturing and these results hold true to about 1800 fps after that a little harder bullet is needed. Ive talked to one well known bullet caster that water drops bullets and about it and the only reason he does it is because of production. The magma machines spit out so many bullets that they were getting damaged dropping out of the machine. But in penentration testing his bulles were loosing there noses because of fracturing quite often. They were just to hard. There are a couple commercial casters who will do bullets for you at the proper hardness for you application one of them is Dry Creek bullets who is an advertiser on this forum(Creeker)  the other is Mount Baldy Bullets. Those two guys understand cast bullets and sell bullets that work in the real world not bullets with gimiky stuff like silver or hardness levels that are rediculus.

[cbrick]

Lloyd Smale is absolutely correct. Too hard is not a good thing and can cause more problems than it cures. It takes ridiculous pressures to keep from leading the barrel and more velocity and better groups are to be had with a more sensible BHN. Most magnum handguns cannot generate enough pressure "safely" to properly obturate the bullet and seal the bore with the BHN much over 20. If your getting barrel leading with hardened bullets try reducing the BHN and see if the problem goes away along with increased velocity and better groups.

I don't have any experience with cast bullet expansion in game but I have 20 years of shooting steel targets with cast. Linotype contains 12% antimony and that is a lot. A whole lot. Antimony is extremely brittle and when using lino and WW-lino alloys I was getting occasional "ringers" (hit 200 meter targets that remain standing). Once I realized that the bullet was blowing up on the target and not delivering it's full momentum I stopped using lino. Since I stpoped using lino I have not had a single ringer. I "assume" that lino will not expand in game but would punch through leaving a smaller wound channel.

Wheel weights contain on average 4% antimony and 1/4 to 1/2 of one percent arsenic (perfect for heat treating) and I get most of them free. Lino is getting both scarce and expensive.

Rick