Tin + H2O Quench = > Accuracy?

[Bigscot]

I have been shooting my Win M94 in .44 mag with the RD 285 GB using WC820 and 2400 using a Williams peep (which I am still working with on this and a M94 30-30) and getting so so accuracy. I did find the last time out that if I got on target quickly and fired, I shot better than if I got settled in and tried to hold really tight.

Anyway, today I shot two good groups (for me, and firing quickly) using the same boolit but this time they were water quenched with tin added. One sized .431 and one .432. In the past they were straight air cooled ww at .431 and .432 with about the same so so results.

Question- is the quick shooting helping out or the tin and water quench? If a mould fills out fine with straight ww and air cooled, why would tin and quenching improve accuracy?

One other thing, I am shooting them gas checked and lubed with LLA.

Thanks,

Bigscot

[Ricochet]

Quenching hardens it (after aging a while) due to the antimony in it going into solid solution in the hot lead, being trapped that way by the quench, and crystallizing out in a much finer grained structure than when air cooled. Tin doesn't help the quench hardening; binary lead-tin alloys soften with aging after quenching.

[Bigscot]

Ricochet,

So I should be able to obtain the same results by just water quenching straight ww?

BS

[Pat I.]

Just my personal opinion and what I've found to be true in my case but I think in most instances harder bullets shoot better with what you're talking about, you don't need to add anything to wheel weights for heat treating, the bullets will be close to full hardness about 12 hours after quench (around 19 bnh), and it takes a lot longer for heat treated bullets to age soften than people think. I have to admit though that I don't use LLA very often so there might be a problem using it with harder bullets and I never have bullets sitting around for a real long time, maybe 3 or 4 months at the most and that ain't often.

[PatMarlin]

Harder bhn definitely improved the groups in 358 Winchester by allowing a little hotter charge with no leading.

I'm waiting on a batch of ACWW to get harder. In one week it jumped from 8 to 10.5, but now it's been 3 weeks and it's still at 10.5.

[44man]

I thought I would toss in here my results with 50-50 WW and pure. It is surprising me! :confused:
The air cooled started at 5 BHN and are now at 8 after almost a month.
My water dropped are at 19 BHN. I never expected this alloy to get that hard. Water dropped WW with the tin brought up to 2% runs about 19 to 20 BHN. Straight water dropped WW boolits are still 20 BHN.
It appears that if you want a tough, yet hard boolit that should expand nicely, adding some pure lead doesn't result in a softer boolit if water dropped. I don't get any leading and they shoot as accurately as my harder alloy.
It must take only a small amount of antimony to water harden them.
The air cooled 50-50 mixed ones will lead some of my guns though. Strange that they test at almost pure lead BHN! I expected them to reach at least 12.

[13Echo]

The secret of wheel weights quench hardening is the presence of both antimony and arsenic. A straight lead antimony alloy will not quench harden as much. Apparently it takes only minute amounts of arsenic to get the effect. Tin improves castability by lowering surface tension , improving fluidity of the molten alloy. Tin is expensive so I would only add to WW alloy if it wasn't giving good fill out of the mould.

44man. What lead tester are you using ? Unless you are melting only the tape on type of WW I would expect your alloy as cast to measure about BHN 8 or 9. Do you have some really pure lead to calibrate your tester?

Jerry Liles

[Char-Gar]

The tempering of WW metal to acheive additional hardness, is a way of getting a cheap hard alloy. If a given load or firearms requires a harder alloy for accuracy, then tempered WW is one way of getting there.

However, harder does not automaticly mean better accuracy. Sometimes softer means better accuracy.

So in your equation WW plus H2O quench equals harder. Harder may be more or less accurate depending on a number of factors.

The cast bullet stuff cannot be reduced to simple formulas. There are far to many variable for that.

[Ricochet]

The secret of wheel weights quench hardening is the presence of both antimony and arsenic. A straight lead antimony alloy will not quench harden as much.
That statement is often made on cast bullet boards, but doesn't fit with what the metallurgists say.

Now it's true that some trace of arsenic is likely to be present in most lead alloys, but while arsenic is one of a whole bunch of alloying metals that will harden lead by going into solid solution and precipitating, there's nothing to be found in references such as the Metals Handbook that it's necessary. Antimony alone will work just fine.

According to the Metals Handbook, 96 Pb-4 Sb has a Brinell hardness number of 8.1 when commercially rolled, 95% reduction. Heat treated at 235 C, quenched, aged one day, it's 24. 26.3. Move on up to 92 Pb-8 Sb and the cold rolled hardness is 9.5, after the same heat treatment and 1-day aging it's 26.3. There's obviously a substantial diminishing return to increasing the amount of alloying material.

A few pages back in the section on type metals we find this:

"The solid solubility of antimony in lead decreases with decreasing temperature below the eutectic temperature, making age hardening possible by rapid cooling of the alloy. Type metals, or lead containing both antimony and tin, likewise age harden after proper quenching. In electrotype metals that contain only a small amount of tin and antimony, this effect is much more pronounced than in the harder stereotype and machine-cast type metals." (Typical electrotype has 2.5-3% of both tin and antimony in it.)

There is also a pair of graphs of Brinell hardness vs. time for a type metal containing 97% Pb, 1% Sn, 2% Sb. As cast (air cooled) hardness is 9 and stays there. Solution annealed for 30 min at 235 C (455 F) and quenched, the initial hardness is 9, but within 2 hours at room temperature it's gone to 15, 17 at 8 hours, 18 at 24, and 20 by 96 hours.

The second graph shows aging of this same quenched alloy at 85 C (185 F). If aged at this temperature immediately after the solution anneal and quench, the hardness peaks at 18 at 1 hour, gradually dropping back to just under 15 by 24 hours. If allowed to age at room temperature for 2 hours prior to heating to 85 C, it peaks at 21 at 1 hour and drops back to 17.5 at 24 hours.

Then there's a table showing the effect of aging on the hardness of type meals, showing for the lower-alloyed ones considerable age hardening with a peak at 6 days, and for the most highly alloyed ones like 82 Pb-6 Sn-12 Sb, there's no significant increase in hardness from the as cast, air cooled condition, just quenched, or with aging. However, ALL of the alloys softened over 6 months aging, but not back to as cast. The 97 PB-1 Sn-2 Sb alloy mentioned above is shown in this table at Brinell 9.2 as cast, 9.2 immediately after quenching, 17.1 at 6 hr, 20.2 at 48 hr, 21.6 at 6 days, and 18.0 at 6 months. 94 Pb-3 Sn-3 Sb is 12.4 as cast, 12.7 immediately after quenching, 14.1 at 6 hr, 16.9 at 48 hr, 18.2 at 6 days, and 16.6 at 6 months. (Why's it softer with aging, though it contains more antimony? It contains more tin, which age softens.)

The book also shows the mechanical properties of several lead-based and arsenical lead-based babbitts, as "Chill cast." They all peak in the 20-22 range for Brinell hardness.

The take-home lesson is: For maximum effect of heat treating lead, use alloys with small amounts of antimony and use as little tin as will give decent casting. Arsenic's nice, but not necessary. A week of aging will give maximum hardness, and they're a little softer after 6 months. If you're using hard type metal, water dropping is still a convenient way to do it, but don't expect much gain in hardness from it. Soft alloys with little antimony will harden a lot more than you may expect.

[44man]

13, I have the LBT tester. Pure lead will show 5 BHN. Since this 50-50 alloy is half WW's, I expected more then 5 to start and 8 to finish. Then water dropped goes to 19!!!
Charger, I only shoot heavy boolits, heavy hunting loads and harder is more accurate for me but I have found the alloy does not matter as long as the hardness is the same or close to what shoots good from the gun. Some of my revolvers need a larger boolit then I can get from a certain mold so I add antimony to WW's so they will grow. If a mold casts a large boolit, then I can go tougher by adding pure lead without an accuracy loss. It still comes down to boolit fit.
The only problems I have with soft boolits is leading with the heavy loads. (I can go down to 10 or 11 BHN in some guns if the boolit fits. Others lead until I get to 20 or 22 BHN.) For light loads they are fine but I don't shoot many light loads.
I find it is easier to just water drop all of my boolits no matter what alloy I use. I see no difference in accuracy and never found a need for heat treating or harder alloys. I don't have any more rifles for cast except the .44 Marlin so I can't talk about those boolits.
I think too much is made about being right on the money with alloys and hardness. I don't find it critical.

[mike in co]

how fast are you shooting them ??

i get excellent accuracy WITHOUT the gas check, but right now i'm only shooting about 1260 fps from an 1894.
ww with real minor tin, h2o ,the 290 gb, sized 432 16 gr of my lot of wc820
mike

[Bigscot]

Mike,

I have been shooting 17 grs of WC820 and 17.5 of 2400 for now. I have 2 jugs of 296 to try also.
BS

[monadnock#5]

You don't say in your first post how much experience you have with a peep sight. If you've got lots of experience, please ignore this post. If peeps are new to you however, it may be that you're shifting your focus from post, to peep to target. When using an aperture sight, focus on the front sight exclusively, and make sure to center the post and not the target. If you're right handed, and putting some shots in the black, and some shots at 5:00 in the 8 ring, you're shifting focus.

[13Echo]

Richochet,

I don't dispute that antimony hardens lead or that it can be heat treated, however arsenic does have a positive effect of hardness and hardenability of a lead antimony (tin) alloy. Marshall, in the NRA "Cast Bullet Book" article, "Stronger bullets with less alloy", on page 125 notes that "metallugists have found that very small additions of arsenic, from 0.05% to 0.5% enhances the hardenability of antimony alloys by a quite disproportionate amount - even though arsenic alone is of little value in strengthing lead. ----- But in combination with antimony and heat treatment, arsenic provides the capability to harden lead much beyond present bullet casting standards." There are similar statements in the Lyman "Cast Bullet Handbook" on page 49.

Jerry Liles

[Bigscot]

Monadnock,

I have been shooting the peeps for maybe 3 years. I do try to focus on the front sight on the target. I think my biggest problem is keeping the front post in the center of the peep. That is why wonder if getting on target quickly and shooting helped. I have wondered too if a smaller aperture would be in order. I read on this forum about people shooting 1-2 in groups at 50-100 yds with iron sights and wonder how in the world they do that. At 25 yds I can shoot ragged holes.


BS

[Larry Gibson]

Bigscot

You don't say how fast the loads are pushing out off the M94 but I imagine they are hefty loads for the 285 gr bullet. You are getting better accuracy because the bullet is heavy and has a lot of enertia. Accelleration is causing obturation that is detrimental to accuracy with your un hardened bullets. The hardened bullets with the same loads are withstanding the accelleration without undue obturation and thus shoot better. Lots of of good info on what causes bullets to harden whn WQ's. My research and experience matches that of Richochet; it is the antimony that hardens the alloy when WQ'd. The presence of arsenic has little effect. A lead-tin-antimony alloy when WQ's can be brittle whereas a Lead-antimony alloy hardens as well but is still ductile and expands without shattering. That's the reason I use 3-5% antimony shot as an alloy for my hunting bullets, WQ'd of course. I started using that alloy after reading Paco Kelly's articles and trying it. It works for me but I'm also experimenting with the two alloy technique discussed by BruceB I think.

Larry Gibson

[44man]

A tiny amount of arsenic is needed in order for antimony to harden. Hard lead shot contains a trace amount as does WW metal. I have even heard it occurs naturally in antimony.
Larry, you are adding it with the shot!

[Pat I.]

The bottom line is you have the perfect alloy for heat treating with the wheel weights. You have the option of from 10 to 35 BNH and anywhere in between if you want to get fancy and start drawing them down to a specific hardness. If you find the gun shoots better with a harder bullet try going with a regular lube to see if it improves. If it shoots better for a couple of groups with the LLA then falls apart try lubing with a regular lube. If it shoots good over the long haul with the LLA stick with the alox.

A lead tin animony alloy will heat treat but it'll heat treat a lot faster and be harder with a little arsenic in it which WW have. I've never mixed a straight lead antimony alloy because antimony isn't something you find on your neighborhood shelf, I understand that in it's pure form it requires a lot of heat to put in in solution, and with the availability of WW why bother.

With mould quenched WW you can cast and HT them today, size and lube them tomorrow morning, and be out at the range shooting a bullet as hard as linotype tomorrow afternoon.

[monadnock#5]

http://www.midwayusa.com/eproductpage.exe/showproduct?saleitemid=429972&t=11082005

Here's a link to a book by Jim Owens that might help you out. Aperture sights are a really wonderful tool, but require instruction in their use. If your focus is shifting back and forth, you will continue to shoot two distinct groups, and never get them all in the black. The book also diagnoses other problems you may be having. I have a copy, it has helped me, and I recommend it.

The book is primarily concerned with competition shooting, but don't let that throw you. You can get helpful insights for hunting applications from the advice therein. If you have a DCM range in your vicinity, give it a try. Again, don't let the competition aspect get in the way. There's always someone or two who will go out of their way to welcome you and share their experience to enable you to become a better shooter. If you ever wanted to find out how good you can hit on a 600' target, the DCM training and matches are the way to go about getting it done.

[44man]

Pat, I buy antimony chunks from Bill Ferguson. He sells a special flux and the antimony melts in at 600 degrees. I add a small amount and some tin to WW metal for one alloy that shoots real good for me. Seems like WW's here are not as hard as what some of you get where you live.

[Pat I.]

44, You're right of course and I forgot all about Bill Ferguson so have to eat those words. The bottom line is still that WWs either straight up or with a chaser is just about the perfect cast bullet allloy and will do anything you need doing. I've used it for everthing from a 50/70 with an estimated velocity of about 1000 fps to a 30x47 with a chronographed velocity of 2650 fps and never felt the need for anything else.

Getting back to the original question I use mould quenched WW in my Marlin 94 with a LBT 280 gr LFN lubed with Blue backed by 19.5 grs of AA #9 and it shoots pretty well, penetrated 8 gallon milk jugs full of water at 45 yds and kept going, and doesn't lead the barrel one iota. What more could you want?

[twotrees]

In the distant past I worked for a Large company that was into Fuel cell and Battery research. The Very BEST Water cooled cast boolits I have ever made were from battery lead that had a large % of arsenic in it. These boolits were glass hard on the outside and dead soft inside (water quenched).

Since that place no longer exists and I now work for another place that Don't like anything gun or bullet related, I've been thinking about tearing apart som eold battery's and use a propane tourch to melt down some of that lead for the arsenic content.

Since coming here and seeing the posts about hardened shot, that looks like a much better way to get that component in the melt.

If it will help I'll get a thermocouple and a data recorder and do a time/temp phase diagram of the cooling cycle of 3 types of melt. Straight WW,,WW with arsenic added (air cooled) and Water quenched. If Y'all think it would be worth the time.

IF I can find a student that will get som SEM time and run all 3 for me we'll try for some intrenal pictures of each.

TwoTrees
(21 years at Ga Tech, Materials Science and Engineering School)
(12.5 years at Westinghouse R&D Center)

[felix]

2trees, go after it, my man! However, we should consider this a pure research project and nothing else. Why? The ability of us shooters to get the arsenic without getting into trouble health wise, and/or where to acquire the arsenic. I don't think most of us is willing to play with batteries with stuff like cadmium included. Arsenic is OK because it is not any more bad than antimony, and besides we can smell the stuff when the concentration gets too high. It's the garlic smell. ... felix

[Ricochet]

You'll also smell like garlic if you pick up some selenium by inhalation or ingestion.

It's not worth fussing about, more a matter of semantics, but it's two different things to say that arsenic enhances hardening (which I will heartily agree with) and to claim that it is necessary for arsenic to be present to allow antimony to age harden after quenching, which is untrue. And I have good metallurgical references to back that up. But as I said myself, there's likely always some arsenic present in our alloys, so I'm not going to worry about it.
:-D

[13Echo]

Ricochet,

I don't believe anyone said that arsenic was necessary for hardening of a lead antimony alloy. What was said was that arsenic enhanced hardness of the alloy when quenched. The fact that Wheel Weights usually contain a small amount of arsenic allows them to be quenched hardened much more than the same alloy without arsenic.

Jerry Liles

[Ricochet]

I don't believe anyone said that arsenic was necessary for hardening of a lead antimony alloy.
44man did. You didn't. I read more into your first statement than you actually said. I've seen the claim that arsenic is a necessary "catalyst" for quench hardening over and over (I think it comes originally from the NRA Cast Bullet Handbook, and thought I was seeing that again. I quite agree that it's a good thing, though surprisingly (to me) the arsenical lead babbitt alloys listed in the Metals Handbook, didn't get any harder with quenching and aging than the closely similar lead-tin-antimony alloys without arsenic.

[PatMarlin]

I thought I would toss in here my results with 50-50 WW and pure. It is surprising me! :confused:
The air cooled started at 5 BHN and are now at 8 after almost a month.
My water dropped are at 19 BHN.

This is an exciting find IMO. Definitely worth experimentation on my end... :Fire:

[Ricochet]

Definitely so! I don't yet own a hardness tester, but as I've often said, my soft mixed scrap that's easily thumbnail dentable like pure lead gets comparably hard to aircooled wheelweights after 4 days of aging after quench. There's enough alloy in there to do the trick. After trying the 50-50 wheelweight and soft lead mixture, I started reducing the amount of wheelweights (since I have a lot more soft lead), and down to 1 part wheelweights to 4 parts soft lead, I can't tell there's a noticeable hardness difference after quenching and aging from the 50-50. In fact, it's not much softer than straight wheelweights quenched. I'm crudely poking it with screwdrivers, cutting it with knives and such. Got to get me one of those hardness testers one of these days!

Oh, yeah: the quenched soft mixtures, after hardening, are still very malleable.

[twotrees]

Cast 2 boolits 1 of dead soft lead one of your alloy. Put them base to base with a ball bearing in between them. Squeeze them togeather in a vice. when the bases of the boolits touch open the vice. Measure the hole made by the ballbearing in the dead soft and the one in the hard alloy. This is your reference. Then try the same with dead soft and water dropped and heat treated. This will give you a reference point as to the relative hardness of the post cast testing.

At least it's better than a thumb nail. (mine are soft from years of abuse)

TwoTrees

[Ricochet]

Makes sense. Sort of a relative Brinell test.

[leftiye]

Lee in his book tells how to expand this to actually give BHNs.

[PatMarlin]

I really like the LEE hardness tester. I could see where it would be hard to use if you didn't have a light over your bench. I bought it on sale. I bet it's as accurate as most.

[44man]

I just found this in one of my books;
"WW's always contain traces of other substances. Key to the success of heat treating is arsenic. The amount of arsenic present doesn't seem to be too critical--just that there be some there."

Some of you oven heat treat to get WW's to 30 BHN and I suppose that is where the arsenic really comes into play.
Water dropping is a form of heat treating too and gives me what I want so I won't go to any more work then what it takes to make a good boolit.
I don't know what arsenic does with antimony but understand it takes such a small trace that it doesn't make sense to try and add more. Almost all of our metals will have a trace of all kinds of stuff in it.
I also found this about shot;
"Magnum grade shot contains a considerably higher antimony content then plain chilled shot. This shot contains 5% to 6% antimony plus about 1.5% to 1.7% arsenic. This formula produces pellets which retain their shape better in the face of firing setback and bore travel."

Plain chilled shot only contains 2% hardener. I suppose it only has a tiny trace of arsenic so it is not a high source of the element but we don't need much anyway.