Okay, another stupid question

[Ian]

Adding more tin than the antimony percentage present gives me the heebeejeebees, most especially when heat treating the part that's most important to the lands and grooves.

Anyway, I set up a little test a minute ago and got the oven going. Three bullets will be tested, each of a different alloy.

1. Lee .458" 500-grain hollow points, COWW plus 1.5% tin

2. Lee .309" 230-grain boat tails, 3 parts SOWW/2 parts COWW

3. ACE .314" 235-grain flat base, 2 parts COWW, one part SOWW, one part pure lead.

I filed flats the length of all the bullets in two places for Brinell testing.

My plan is to heat them at 440F for an hour, grab them in the middle with needlenose pliers, and dip the bottom third of each bullet in cool water until the sizzle stops and then toss them on a dry towel. I don't have any powdered lime but if the bullets were poked into a tray of that nose-first it could be used to prolong the nose cooling.

 

[358156 hp]

According to Veral at LBT filing the bullet will give erroneous results via work softening the alloy. I've not tested this myself but it sounds logical.

I plan to file the flat before heat-treating. It will be a good sized flat so as to allow my LBT tester a solid flat surface to work properly.

I found Verals thoughts on this to be logical as well.

 

[Chris]

Adding more tin than the antimony percentage present gives me the heebeejeebees, most especially when heat treating the part that's most important to the lands and grooves.

I'm interested in your experiment. Regarding the antimony content of Paco Kelley's bullets and tempering technique: I believe that Lawrence Magnum shot has an antimony content of 5-6%, so the tin/antimony ratio would not be out of whack according to current thinking.

 

[fiver]

I get even more worried about 5% tin in magnum shot.
back in the 90's it would have been no big deal but now, no way.

magnum shot comes in waaay too wide of an antimony content.
you used to be able to count on it being @ 5% antimony.
now it's 2-4-6% and that's just what Remington is running.
win and Fed are about the same depending on the cartridge cost [and some will surprise you]
even some aftermarket makers are at the 2% end others more at the 5% end [but impossible to find under 2$ a lb.] and some of it depends of shot diameter.
even with a chart [based on actual tested alloys] your still just close and sometimes just guessing depending on the day you bought the shot.

 

[fiver]

I just tried for an hour to upload my chart showing the antimony content of various shot brands from around the world.
federal is using shot from spain in some of it's hulls. [the same as Rio 3.2% antimony]
the stuff from france is softer.
eagle brand shot is 2%. [but they can't get the right sized shot in a bag]
old Lawrence magnum is 5% their new stuff is just over 4%.
west coast magnum is below 3%.
northwest magnum is right near 3%
now the good news.

Winchester AA's are tops in antimony, followed by Remington STS @6%, and the [now discontinued] federal gold medal is still over 5%. [I don't care what the box says they quit on us]
those are your 8-10$ a box target shells.
they all make their own shot, and no you can't buy it any more.

 

[Rick]

Does that chart give arsenic percentage?

 

[Ian]

This, from the Beartooth article, is what I meant by too much tin:

"I decided to concentrate on the use of alloys that would fall in that portion of Marshall’s graph bounded by 11% antimony and 20% tin to insure ductile bullets that would not shatter upon impact."

Not that he used that alloy, but was within the bounds of the graph, anywhere within which is still an awful lot of tin.

 

[Ian]

Ok, first tests. I used an air-cooled and aged control from each, though the 500-grain control is only about ten days old. The other two are close to a year old now. Bullets were pulled from the oven and bases immediately dipped in a pan with .3" cool water in it for three seconds and dropped on a towel. BHN tests completed within 20 minutes of quench. Numbers are average of two tests spots per test point on each bullet.

Lee 500- Control = 10.4 bhn, no change to heat-treated ones.
Lee 230- Control = 11.8 bhn, nose/base test around .082-6", below 8 bhn, no obvious nose/base difference. This alloy is tough to get exact for some reason.
Ace 235- Control = 14.3 bhn, nose/base exactly .082" each, just below 8 bhn.

Stay tuned.

 

[blackthorn]

I do not even pretend to know much about this subject, other than what I have read. That said, the question of whether there is a difference in hardness between the outside and inside of a heat treated bullet has often been on my (small/foggy) mind. When we talk about pre-filing a flat on a test bullet to avoid disturbing the hardness, would not that process simply move the test surface from a curve to a flat and provide nothing in the way of information on what takes place within the bullet's interior? Or am I missing something? It seems to me that in the absence of some form of sophisticated electronic testing equipment we will forever remain in a state of unhappy ignorance.

 

[fiver]

they gave nothing on the arsenic content.
their was only one mention about it.
that was from someone that read a post of mine about substituting sulpher for arsenic in a discussion on the Boolits site.
as far as I know the As. content has stayed steady at about 0.5% in shot [tower dropped] the newer methods don't tower drop shot anymore but blow it upwards and can control the time 'it falls' so they have allowed the As content to drop near ww levels of about .24-.25 or thereabouts.

shot shells and their components have taken a huge swing towards the engineered to barely work once side in the last few years.
I thought the metallic components had been going that direction recently but I am expecting something to take place in the next 10 years that will make things pretty tough on us as reloaders.

lot's of lower priced copper washed or plated steel cased ammo from former reliable factory sources is what my crystal ball is predicting.
I'm just predicting this but we could be seeing 10$ a box 30-06 ammo again just not with re-useable cases,
or with cases with the ability to re-use them more than once.

 

[Ian]

Stockpiling components is the answer. Or go back to the caseless ordinance that was used to establish this country's independence nearly 250 years ago.

Blackthorn, we're not testing the interior right now, just the outside. The pre-filed flat gives a more accurate testing surface. I'm trying to make soft-nose bullets from mid to low-antimony alloy by only heat treating the base for hardness.

The idea is that the noses will be the base-line, air-cooled temper of the alloy after they age and the bases will be the maximum quench hardness after aging. Both will change some right after the heat treat, back to as-cast state.

 

[Rick]

I do not even pretend to know much about this subject,

Sounds to me like you know more about this than you think you do.
.

 

[358156 hp]

For anyone who isn't familiar with the heat-treating process, here is Ricks article on heat-treating lead based alloys: http://www.lasc.us/HeatTreat.htm

This is the prior research we're trying to build upon.

 

[popper]

I tried a reverse version of the BT technique. Place WD FP nose down on a hot plate. It doesn't take much heat/time to anneal (soften) lead. IMHO a pan of chilled water, metal plate touching the water with nose holes and hot air (hair dryer/etc.) blown across the noses of previously HT boolits.

 

[Chris]

I am very interested in how quench annealing and de-tempering actually work, particularly with different alloys. My LBT hardness tester is lacking a part so I can't right now make measurements.

I have de-tempered the noses of bullets. Oven hardened and water quenched bullets, I've done both using an alloy of OLD Lawrence mag shot with added 4% tin, pretty much like Paco Kelley advised. Play a torch flame on bullets set in a water pan, the color of the nose subtly changes color then tip the bullet into the water. One more second of heat will slump the nose.

As far as I can see this softens the noses but not the bases, based on a subjective scratch test. Would one of you guys with a hardness tester try this and report the nose vs. base hardness? I have a hunch this is the easiest way to make softer nose hunting bullets from an alloy that can be substantially hardened. I also question how long the bullet nose remains in softer condition over time, I read an article that indicated approximately a few months... does that make sense?

 

[Rick]

De-tempered = Annealed.
Play a torch on the noses and tip over into water and you have hardened them assuming you got the heat high enough, not annealed them.

I've never tested how long an annealed bullet will maintain the same BHN but I have with heat treated bullets and the change is far slower than in most written accounts. I HT'd about 100 RCBS 35 200's to 30 BHN. 10 years later I found them stashed under the bench and figured they would be putty by now, they were still 26 BHN. So yes they did age soften but not much and very slowly.
.

 

[Chris]

De-tempered = Annealed.
Play a torch on the noses and tip over into water and you have hardened them assuming you got the heat high enough, not annealed them.

I've never tested how long an annealed bullet will maintain the same BHN but I have with heat treated bullets and the change is far slower than in most written accounts. I HT'd about 100 RCBS 35 200's to 30 BHN. 10 years later I found them stashed under the bench and figured they would be putty by now, they were still 26 BHN. So yes they did age soften but not much and very slowly.
.

Rick, we need to explore this further with hardness measurements. I think what I have done is to soften the noses, the opposite of what you suggest.

You take oven heat treated bullets, BHN >21. Simple to test if someone could oblige. Make a very hard bullet by heat treating the bullet, heat the nose to almost slump while standing in water, tip them over. I believe that the base stays hard and the nose gets softer. There's an objective test that unfortunately I can't perform now... but we should all want an answer.

Rick, I agree with your findings regarding age softening of hardened bullets. They soften very slowly, almost not enough to be concerned about.

 

[Brad]

Heating the nose then quenching it hardens the bullet. Heat it and let it cool slowly and it softens.

 

[Chris]

Heating the nose then quenching it hardens the bullet. Heat it and let it cool slowly and it softens.

Guys, I think that is not necessarily true if you begin with an oven hardened bullet. Otherwise correct.

If you are right then I can take a bullet of 25 BHN and harden the nose further by heating it. Or possibly it has no effect.

There is a very simple test if you have two items, oven treated bullets and a hardness tester. Also a pan to put some cold water in.

Brad, my hypothesis is that tipping the bullet into the water is only to to prevent the base from also softening. The thermal conductivity of lead is high and heat affects the structure of our alloy quickly. The bases have to stay cool as long as possible.

Based on my subjective testing the noses of very hard tertiary lead alloy bullets can be softened substantially by the method we are discussing. Objective testing will increase our body of knowledge. Anyone willing to try it?

 

[Brad]

If the base is in water it can't rise above 212 F. That is what the water does is keep the base cool.
Less nose above water and less nose is annealed, more exposed means more is exposed.