Low Antimony bullet tutorial, pls.?

[Canuck Bob]

I'm really getting cheap. Babore has a number of interesting threads about low antimony alloys and their performance. Fussing over a run of cast bullets suits me. So I'm willing to water drop and more likely to OHT, already set-up with a shop toaster oven for non-food use.

My lead alloy base is #9 Mag shot, roofing scrap, lead-free solder. The antimony content of mag shot is listed anywhere from 6-4% with small shot richer plus arsenic as most already know.

Babore lists decent HT performance from alloys that look like 2% or so from my rough calculations. The air cooled hardness looks like it might be fine for PB velocities (11-12bhn ?)and HT will handle anything I need(upper teens bhn?); 32-20, 444, 303B only but probably some paper patch for the 303 and maybe 444.

How low can antimony go before it won't HT worth a darn? Some accounts say 2% hardens but a longer wait is required. Some seem to disagree and discount 2% Sb as non hardening. I was hoping an alloy like 97.5/2Sb/0.5Sn would work to ease my costs as much as possible without alloying up a bunch of marginal bullet lead.

Ingot casting starts this weekend on the shot, scrap lead next week. Later I'm hoping to alloy 1 ingot shot 2 ingots soft lead and some solder. Am I dreaming?

[GP100man]

Nope , your not dreaming !

I run an alloy of 94%lead, 4%tin & 2% antimony ACed to `bout what I wanna do in 357 mag .

The tin tuffens the boolit a bit without hardening it , this works wonders with a 358156 plainbased (GC removed by Buckshot) HP mold from 900-1200fps.

But I`ve reamed my cyl. to be .001 over bore & fit is crucial to using this soft an alloy (10.5-11.5 bhn) with these pressures !!

I also shoot this alloy in my Mosins & A Remington 700 in 30-06 using the 314299 mold & get acceptable results to 1850 fps . All boolits sized to .314".

[runfiverun]

i like my alloy of 1% tin 3% antimony a swipe of arsenic in there somewhere.
plain up for revolvers, waterdropped for most rifle applications.
use a harder 4/6 alloy for some things that like it better.
but i can work 90+% of the time with that 1/3 alloy and might could do 100 if i wanted to heat treat.
you can use other thing besides arsenic to help your alloy heat treat.
and other things besides antimony to harden an alloy.

[outdoorfan]

I think my ww's have lower antimony than the published 4% because when I alloy to 50/50 with soft lead I end up with boolits that are 8.5 air cooled and 21 oven HTed. I usually add about 1% tin to the mix as well. You'll be fine. Come on board. I'm pretty sure you can even go down to 1% or so antimony and still HT for some hardness, but it'll take longer to get there. My 50/50 mix is at full hardness (I didn't say uniform, necessarily) within a couple days of HT'ing.

[geargnasher]

Bob, you're wide awake. You have a pretty good handle on what does what, and those that say less than 2% is a waste of time either don't heat treat, or doen't know how to wait a few weeks. I've heat-treated ~1% Sb alloys with equal amounts of tin to get in the low teens with bhn. As you know the trace arsenic makes a huge difference in age-hardening timeline and ultimate hardness.

If you're using lead containers such as those from nuclear medicine labs, you may find some of them have a perfect boolit alloy mix of Sb and Sn already, and it makes fine boolits. Downside is you have to wait about three months for air-cooled boolits to reach final bhn. I attribute this to lack of arsenic, because I can mix Magnum shot, roofing lead, and solder much the same as you have to get the same proportions as the isotope lead, and it hardens in a week.

Gear

[geargnasher]

I think my ww's have lower antimony than the published 4% because when I alloy to 50/50 with soft lead I end up with boolits that are 8.5 air cooled and 21 oven HTed. I usually add about 1% tin to the mix as well. You'll be fine. Come on board. I'm pretty sure you can even go down to 1% or so antimony and still HT for some hardness, but it'll take longer to get there. My 50/50 mix is at full hardness (I didn't say uniform, necessarily) within a couple days of HT'ing.

Maybe so. I get around 10 air-cooled and 20-22 water-quenched, 24-26 OHT depending on the batch. I figure clip-ons at about 3% Sb, that's the way they act when tested under various conditions. Calcium, copper, nickel, etc. all have an effect on how your alloy behaves, and ww are sort of a garbage disposal for the non-ferrous metals industry.

Gear

[outdoorfan]

Maybe so. I get around 10 air-cooled and 20-22 water-quenched, 24-26 OHT depending on the batch. I figure clip-ons at about 3% Sb, that's the way they act when tested under various conditions. Calcium, copper, nickel, etc. all have an effect on how your alloy behaves, and ww are sort of a garbage disposal for the non-ferrous metals industry.

Gear


Don't know if it makes a difference (probably does), but I water drop everything. The ones I want air-cooled get annealed in the oven at around 450 degrees for an hour, then slowly cool without opening the oven door after the heat has been shut off. This way everything is uniform every time. I have had higher bhn readings when using the conventional air-cool method of dropping out of the mold. Probably a waste of time, but it's not a big deal to me and it's the way I like to do it. I also don't shoot near the volume of some people here.

[Canuck Bob]

Thanks, I'm a low volume rifleman. Our regs make handgun shooting just too onerous for me. You can't carry to the field to plink and that is my favored pastime.

This is encouraging. My wife and daughter got back from the orthodontist on Friday. The orthodontist is smiling, I'm not!!! Oh well, my beautiful 9 year old can melt stone with her smile now, it will be something else in a year or two.

When I study it seems that as an alloy it is beneficial to have tin and antimony alloyed up close to equal. Something about a different type of alloy. Is this important at these low levels? However, with the reported AC and OHT BHN numbers I'm already relieved about this.

Outdoor fan, I'm like you. I don't mind the fussing that some don't like. I can control my HT efforts with an oven, my alloy with known commodities. I've noticed that the masters around here and on the CBA site tend to be very detailed and specific with their advice. It always includes discussions of fit, alloy, lube, tool mods, and such. There seems to be a direct relationship between consistency in details and the old pros. I'm realizing that learning cast is a fun process and then you get to make explosions by burning powder and launch lead downrange accurately, did I mention cheap too.

[geargnasher]

Bob, what you've been hearing about a "different type of alloy" is probably references to an intermetallic compound called Sb/Sn. When you have lead, antimony, and tin present together in molten solution, the Sb and Sn tend to "link up" forming a pseudo-element that has properties all its own. Take Taracorp Magnum alloy, for example. It's a ternary Pb/Sb/Sn in the 92/6/2 percentage range. It doesn't behave as such, though, it behaves as 92% Pb, 4% Sb/Sn, and 4% free Sb. The intermetallic compound Sb/Sn has properties of hardness, toughness, and malleability that exceed those of either element, and does in fact lend those properties to the alloy more than either could alone, or separately together if they didn't form the intermetallic compound. This intermetallic is what makes Lyman #2 so good, it's actually 90% Pb and 10% Sb/Sn, acting as a pseudo-binary alloy rather than the ternary that it truly is, and it has properties truly greater than the sum of it's parts due to how they link up.

The proportions of these three metals within the solution have drastic effects on melt point, freeze point, slush (or mush) phase duration, and the microstructure of the frozen alloy due to the different primary phases of solidification. With certain proportions, sometimes the Sb freezes first to make the alloy "slushy" as it's cooling, sometimes it's Sb/Sn that freezes first, sometimes it's eutectic (all freezes at the same time) like Linotype, sometimes it's the lead that freezes first, it all depends upon the proportions. Which metal/compound is on the primary phase of solidification is important because it affects the grain structure of the solid boolit. An oversimplified view would be that if the proportions are such that pure antimony or Sb/Sn freezes first, the metal will be harder and very brittle. If Pb freezes first, it will be much softer and more malleable. Lyman Cast Bullet Handbook #3 says that With WW metal or Lyman #2, the lead will freeze first before the Sb/Sn and free antimony in WW and the Sb/Sn in the balanced Lyman #2, making them more malleable and softer than, say, monotype which has Sb/Sn as the primary phase of solidification (freezes first).

You don't want more tin than antimony under any circumstances, because the free tin will form nodules after everything else is solidified, and this plays hoc with the strength of the alloy's surface and makes ugly "tin patches" on them, as well a simply being a waste of tin, since any tin percentage beyond the amount of antimony present doesn't really have anywhere to go other than to mix with the lead throughout the alloy, where it doesn't do any good for hardness beyond about 11 bhn.

My bottom-line "modus operandi" for most smokeless-powder rilfe shooting is to use an alloy that has at least 1.5-6% Sb, up to 2%Sn (though frequently less), and hopefully a trace of arsenic. Water-quenching and heat-treating have, in the last year or so, really surpassed the results I used to get by "alloying up" to the same hardness. For example, properly water-quenched boolits (the way I learned form the postings of BABore and 45 2.1) made of clip-on wheel-weight alloy mixed 50/50 with roofing lead and a dash of extra tin (they don't add tin, I do), will get a nice, tough boolit at about 18-24 bhn that will outperform straight linotype (at 22 bhn) in every rifle I've tried it in. This alloy works so well I'd recommend it to anyone even just for punching paper with rifles, and it's cheap on expensive Sb and Sn. Air-cooled, it ends up in the 9-11 bhn range, perfect for .38 Special, .45 Colt and ACP. My best estimate is it's around 1.5-2% antimony, 1-1.25% tin (the way I make it), and the balance lead and trace arsenic, copper, etc. ect.

Hope this helps some,

Gear

[Canuck Bob]

You should write for Lyman. Now I understand what they are trying to say about the SN,SB alloy.

I am going to clean my shot tomorrow and my scrap roof lead next weekend. Then cast my first bullet and start my hands on training. I think that my idea of 1/3 shot 2/3 soft lead ingots will work just fine with a little sweetening of tin.

It does also appear that this group is advancing the low antimony technology at the right time. The assault on lead in easy distribution is going to pick up pace quickly now. The general public couldn't care less and heavy metals have caused some serous health issues sporadically.

Good scroungers can stretch the WW and performance further now. Were Babore and 45/2/1 the ramrods here for this change?

[runfiverun]

nope. fit is the deal.
many have disagreed with the written "hard rule" for years.

manipulating an alloy is economical and in many cases the better performing boolit.
using a manipulated low antimony alloy for hunting is the way to make a boolit perform. especially if you toughen the base with water dropping and anneal the nose back to the original alloys hardness, or make a dual alloy boolit using pure for the nose tip.
zinc.copper,bismuth,arsenic,sulpher and others can do the same thing as antimony/whatever alloys just in different ways.

a guns fit, chamber alignment, groove depth,bbl condition,and twist rate will help things along easier.
but fit, the shape of boolit compared to the throat and the diameter relationship of the bbl/boolit along with a good lube to help seal will get you pretty far along on it's own.
and will make accuracy/velocity gains come much easier.

you don't need an oversized boolit either, it just needs to fit properly.

[geargnasher]

Amen to that, R5R, the rest of the story. One of the hardest things to do here is to keep a pinpoint discussion in the perspective of the overall situation. The way I'm learning to see it now is everything affects everyting else when loading and firing cast boolits. There are dimensional criteria to be met, both with the brass and the boolit (both must fit the gun to a "tee"), a balance of peak pressure and rate of pressue rise/peak/fall, alloy propeties to match, lube that has the correct viscocity and just enough lubricity to match the velocity and pressure, and the bazillion little things like filler, crimp, primer selection, case neck tension, state of anneal, on and on. The really frustrating thing for me is that it's difficult to make hard and fast rules about anything, except Fit is indeed King, and everything else "depends".

Gear

[303Guy]

Explained so I can understand it - thanks for that geargnasher. :drinks:

You didn't mention that the trace elements like arsenic, copper, etc, are grain refiners. Perhaps you could give an explanation of how grain refiners work?

[44man]

Gear has created a sticky---"WW's are the garbage disposal" needs to be framed and read over and over! [smilie=l:
I have fooled with all kinds of alloys and water dropped WW metal works best for me and pure accuracy from my revolvers but for fast powders I will go a little harder. I don't like super hard metal like straight lino. Just a waste.
PB needs harder and WW's are good. As you soften, groups open. A GC helps bring something to paper again. Water drop and groups get real small with either boolit. PB will stay neck and neck with a GC.
50-50 needs to be water dropped or oven hardened but a PB will not shoot small groups. Add a gas check and most shots go in one hole but there will always be a few fliers at 50 yards.
99% of shooters will never notice the fliers and at 25 will never see them. This is fact because not many are after what I am. I am still trying for a one hole group at 100 yards with cast, I have been close but no cigar yet.
All kinds of lead can be shot and if everything is correct, you will not lead the barrel. 50-50 shoots very clean but I am not just looking for leading and needing to solve it, that is the last thing I consider.
You can shoot much softer too. The point is that as the alloy changes, so do the groups and every group can be read and corrected just with the alloy and hardness. Sure you can fiddle for years with one soft alloy and all the powders until you get it to shoot fairly good but you are stuck with just the one boolit, one powder and one charge.
This is where I am always at because softer is better for hunting but harder is better for accuracy. There is a window of velocity where hard works just fine for deer with a .44 and up and a good meplat.
Balance has to be found because the last thing I want is a flier at a 100 yard deer.
As you work alloys, see what happens at 50 yards on paper. You really can read those groups.
I see more and more guys posting about groups from large caliber revolvers shot at 10 yards, I just can't understand that at all. Why not stick the muzzle against the paper? :holysheep Why did you buy a .44 or .454? Just swing the barrel and knock the deer out! [smilie=l:
Gear always makes a lot of sense and has it right. Yet it is still what the alloy does from your gun and you must be able to alter it.
I laugh when a guy shoots great with jacketed and expects a 30 to 1 boolit to do the same. Hey, the squirrel ran up the other tree! [smilie=f:

[Canuck Bob]

For a beginner I had to break it down to a number of learning tasks. These work for me and my style. I knew I was going to cast eventually. First I got the urge to buy a LEE mold and hotplate and give it a try.

Then I started realizing from posts that there was a lot going on with cast as a group. I gravitated to the rifle line of study. The pistol guys work hard at their precision but it also about steady supply of lead and loaded ammo. Some of those guys really shoot a lot. So I figured to start I'd pick a single direction for cast learning then I found each rifle considered needed different considerations.

Gearnasher's comments about everything effecting everything else is dead on. What is becoming fun is how well I know my guns now. I've owned a 444 Marlin for 35 years. I can handle that gun like pointing a finger. But now I know a great deal about the complete package, micro-groove rifling, bullets and slow twist rifling, a long freebore and a throat/leade like a curb, .431 groove barrel for a speced .429! I also know that while camping in Griz country an LBT heavy cast with low antimony but HT hard will protect my family as well as any bullet made. How could this be more interesting and fun.

[btroj]

I give you credit for limiting your initial learning to one small area. This will make your education much easier.
I used to be a hard all the time guy, now have decided that agaric WW or WW cut with lead is ideal for most of my shooting. I tend to water drop everything out of convenience as it fits my casting rhythm.
Gear has given you enough knowledge to be successful in aout any area of casting.

Now go shoot those bullets.

[cbrick]

nope. fit is the deal.
many have disagreed with the written "hard rule" for years.

No kiddin, I've been saying for years that the term "hardcast" is evil and does nothing but pollute the minds of new casters and buyers of commercial cast bullets.


zinc, copper, bismuth, arsenic, sulpher and others can do the same thing as antimony/whatever alloys just in different ways.

Either I am reading what you mean incorrectly or the statement is wrong. Many things can replace arsenic in a lead/antimony alloy and do the same thing. Arsenic is the most commonly used in the metals industry and thus most bullet casters simply refer to arsenic as the hardening agent. However, not arsenic or any of the other elements in the percentages in bullet alloy will do a thing to harden your bullets any significant amount without the antimony. Think of the arsenic as a catalyst that enhances the hardening of a Pb/Sb alloy well above what the percentage of very brittle Sb would suggest.

As to the OP's original question, I think your lucky with WW of recent manufacture if you have 2% Sb. Todays WW will either quench or oven HT very well so yes, 2% Sb will heat treat. The strengthening (hardening) time curve will be effected, A 2% Sb alloy will take longer to reach its final hardness than will a 6% Sb alloy but harden it will. If you check the BHN of a recently cast 2% Sb bullet you could well incorrectly surmise that it did not harden. Waiting a week or two will be a real eye opener.

A proper bullet fit can help make up for other wrongs such as too hard of an alloy for the pressure/velocity, pressure rise, twist etc. Proper bullet fit is the very first thing that needs to be looked at in an ill performing load, not the alloy.

Rick

[geargnasher]

My last few major clip-on WW smeltings from several years of collecting have consistently yielded alloy that casts boolits that end up in the 13-16 bhn range, which is significantly higher than commonly accepted values for WW metal even from times that it was known to have double or triple the amount of antimony that they do today. I'm working on a batch right now that comes in about 15.5 with 1% added tin air-cooled and heat-treats to over 30. I think many folks are mixing all the clip-ons and stick-ons together and calling that "WW metal", and since most of the stickies I melt come in around 7 bhn or less that would significantly change things. I'm wondering how much the impurities are affecting hardness these days, and how much calcium is in there from recycled batteries. It also seems that WW metal just doesn't cast as well as it used to, and that foundry-certified alloy is always better. I have a pile of ingots from the Modified WW Group Buy and it air-cools to 11.4 bhn and contains 4% antimony and .25% arsenic. W-T-F?? If modern WW contain half that much antimony, why are they so much harder than the foundry alloy? The answer lies in all the other junk that's either put in or left in the low-quality recycled lead the WW manufacturers are buying. If I had the money to throw at it, I'd get this last batch of 350 lbs I alloyed-up assayed so I could see just exactly what was going on with the excessive hardness.

Gear

[runfiverun]

things like bismuth will harden lead just like antimony will.
arsenic is a grain modifier, so is sulpher.
zinc will harden an lead alloy.
copper adds something to the mix also but it acts something like excess tin as the boolit cools.
but not with the soft lead spots.
some other metals/minerals that escape me right now also affect an alloy.

[geargnasher]

Explained so I can understand it - thanks for that geargnasher. :drinks:

You didn't mention that the trace elements like arsenic, copper, etc, are grain refiners. Perhaps you could give an explanation of how grain refiners work?

You are correct, that's how arsenic works, not sure about copper. The dentrites formed by Sb/Sn are smaller and more well-linked within a ternary Pb/Sb/Sn alloy than Sb dentrites alone, that's what gives the alloy more of what many of us techically call "toughness". My understanding of arsenic's role is that it actually creates a "cross grain" dentrite pattern among the other molecules which serve to break up any forces along the weak direction of the antimony and lead dentrite formations.

An analogy that comes to mind is with wood. Take coarse, fast-grown Yellow Pine, it has strong, large, linear, hard grain layers separated by weak growth layers and is very apt to split with any disturbance along the weak points. There are no strong points latticed between the strong layers to break up this grain structure, so a point in the board that is stressed beyond it's yield point will split a great distance, often until encountering a knot or the end of the board which dissipates the force. Now consider Maple, Birch, or cherry wood. Fine-grained woods that are made up of smaller, more concentrated layers, and cross-grain patterns that tie the primary grain paths together. The cellulose fibers themselves aren't all that much harder than the Yellow pine, but they are arranged in a fashion that diffuses stress well within the material, and both it's elasticity and yield strength are greater.

Anyone who has a copy of the 3rd Lyman casting book can see from the photos on p. 47 that TIN is actually one of the most dramatic grain refiners we can use, but it has limitations to overall toughness unless interacting with a significant amount of antimony.

Gear

[felix]

Strad (Stradivarius) Violins (mega bucks) are made from peculiar White Spruce grown in only certain areas of the world that properly render (picking up which negative ions) soil potassium, and a small amount of sodium. The backing/bottom of these instruments used some kind of maple. These items depend upon the grain structure not yet defined for repeat manufacture. Hence the value. ... felix

[geargnasher]

I didn't know about the trace elements in the wood, that's interesting. Those violins are also made such that the back panels and front have four zones of resonance, exactly tuned to the four notes of the strings. The resonant areas are tuned by shaving wood by hand and tapping the resonant zone until it is exact. The location of the bridge and internal bass bar are also, obviously, crucial. A little tidbit I remember from a class I took in college years ago called "The acoustical foundations of music", which was a physics credit. Also, the violins may or may not be tuned to A-440, many orchestras of antiquity were tuned a few cycles under, probably to suit the ear of the conductor or to match the unique tuning of the lead instrument.

Gear

[felix]

Cool move, Gear. Never hurts to take a practical course after learning the underlining physics. ... felix

[HDS]

Interesting thread this.

I have lots and lots of pure lead, a fair amount of tin, and hardly any antimony (I got some wheel weights). If I am lucky I could get a 1% mix of antimony using my wheel weights and easily 1-2% tin. I don't require much BHN though I want to shoot mostly .44spl rounds and for that I think I can live with 9-10bhn and for magnum loads I am looking at 1200-1300fps max so I don't think more 12bhn would be required.

I have a dedicated oven I can heat treat in, I don't think I would need to heat treat a lot though, going by what I read in Glen Fryxells guide on casting.