Changing alloy for lower or higher Tin, Alloy

[huntinlever]

Another thread I started is basically unrelated, so I'll start one here.

I used to cast COWW: PB 1:1, with enough added 95/5 solder to bring it to Tin 2%, antimony 1%, Pb 97%, trace arsenic. 425 grain bullets cast very well.

I'm thinking of adding in some lead to my 1:1 Pb:No. 2 alloy (est. Tin 1.67%, Antimony 1.67%, Lead 96.7%) for a final estimated 1.25% Tin, 1.25% Antimony, 97.5%, in order to increase the bullet weight closer to 405 grains as cast. You guys see any issues with quality - fillout, etc. - going to this lower tin and antimony content?

On the other hand, I can buy 5# of No. 2 and add it to 40 lbs of my existing alloy for a total of 2% tin, 2% antimony, 96% lead. Weight will be lighter still, but this 2% each of tin and antimony is common, and I'm wondering if it might help with consistency.

Thoughts?

[Der Gebirgsjager]

I'd go with option #1, adding some lead. You could heat it up, take half out with a dipper, and experiment on the other half.

DG

[Bazoo]

Adding more lead to your alloy will make your bullets heavier, not lighter. Having only 1.6% tin and 1.6% antimony will still cast good however.

[huntinlever]

Adding more lead to your alloy will make your bullets heavier, not lighter. Having only 1.6% tin and 1.6% antimony will still cast good however.

You might have missed it - yes, I talked of adding lead, lowering the total tin and antimony to 1.25% each, but upping the bullet weight. Just didn't know if that low a tin/antimony content would pose a problem in terms of fill out, etc.

Thanks, guys. I'm leaning to this option as well. For one, I think I've been wanting too high a BHN (I water quench), because I was trying to emulate the original BHN estimate (10.6). This would drop me down to 10.1 before quenching, which I think is still plenty hard. Just wanted to confirm the bullet quality as cast would likely be OK with the lower tin/antimony.

[Bazoo]

I got discombobulated! Yes you will get good fillout with 1.25% tin and 1.25% antimony.

[pworley1]

It should work fine in my opinion, but you will never know until you try.

[JonB_in_Glencoe]

Another thread I started is basically unrelated, so I'll start one here.

I used to cast COWW: PB 1:1, with enough added 95/5 solder to bring it to Tin 2%, antimony 1%, Pb 97%, trace arsenic. 425 grain bullets cast very well.

I'm thinking of adding in some lead to my 1:1 Pb:No. 2 alloy (est. Tin 1.67%, Antimony 1.67%, Lead 96.7%) for a final estimated 1.25% Tin, 1.25% Antimony, 97.5%, in order to increase the bullet weight closer to 405 grains as cast. You guys see any issues with quality - fillout, etc. - going to this lower tin and antimony content?

On the other hand, I can buy 5# of No. 2 and add it to 40 lbs of my existing alloy for a total of 2% tin, 2% antimony, 96% lead. Weight will be lighter still, but this 2% each of tin and antimony is common, and I'm wondering if it might help with consistency.

Thoughts?

The numbers don't add up in what I highlighted, maybe you have a typo?

OK, with that said, My main alloy is 3-3-94
When I want something softer, I will blend that alloy with Pure lead at 1:1 for 1.5-1.5-97 and Casting quality does not suffer.

Another thing that you may be aware of, once a Lead alloy has less than 2% Antimony, it doesn't respond as well to water quenching.

[huntinlever]

The numbers don't add up in what I highlighted, maybe you have a typo?

OK, with that said, My main alloy is 3-3-94
When I want something softer, I will blend that alloy with Pure lead at 1:1 for 1.5-1.5-97 and Casting quality does not suffer.

Another thing that you may be aware of, once a Lead alloy has less than 2% Antimony, it doesn't respond as well to water quenching.

Sorry Jon, good eyes. Should have been 2:1 Pb: No. 2.

Great info, thanks. Not sure why I'm sticking on wanting more weight - might be the holdover from the 425 grains, and a general bias to liking heavy for caliber. No logical reason, actually. I've heard people talking "above 2% tin, it doesn't hurt anything, but it's a waste as the tin doesn't do much past 2%." Hope I've repeated that correctly. Your thoughts? Obviously you disagree, what's your thought process on going to the 3% each?

Thanks on the info on <2% antimony and water quenching. I wasn't aware of that. Truth be told I think I got my original alloy from a guy on Marlin Owners, old school, who shot a Ruger No. 1, 465 grains, with 50:50 COWW: Pb, water quenched, and I just went with it (old timer, convincing dude). I'm getting 0.25% tin, 1% antimony, 0.13% arsenic. I used to add in 95:5 to bring tin to 2% but that still left a low percentage on the antimony. Never hardness tested but I'm guessing much softer than I thought?

[huntinlever]

I got discombobulated! Yes you will get good fillout with 1.25% tin and 1.25% antimony.

Right there with you man.

Great, thanks. Your thoughts on water-quenching v. air-cooling at these percentages?

[huntinlever]

It should work fine in my opinion, but you will never know until you try.

Thanks.

[JonB_in_Glencoe]

SNIP>>>
I've heard people talking "above 2% tin, it doesn't hurt anything, but it's a waste as the tin doesn't do much past 2%." Hope I've repeated that correctly. Your thoughts? Obviously you disagree, what's your thought process on going to the 3% each?

Sb and Sn in a lead alloy form a bond, which creates toughness, not to be confused with hardness. When they are out of balance, the alloy takes on different characteristics. More Sb means more hardness and brittleness. More Sn means for malleability. So it all comes down to what you want your alloy to do. I think that a lead alloy with balanced Sb and Sn is the best all around answer in general. But if you need a harder alloy for a high pressure rifle load, you'll want more antimony...and if you want maximum expansion of a hollow point, then having more Sn is your friend.
.
So why did I go with 3-3-94 ?
I did some measuring of hardness of Lyman #2 (5-5-90), comparing to 4-4-92 & 3-3-94. I was surprised that there isn't that much hardness difference, I would have thought the comparison curve would be more linear, it is not. Theoretically the toughness factor likely increases more so, but I have never tested/experimented for that. Of these three alloys, the hardness doesn't start dropping off significantly until the Sb and Sn levels go below 3% each. So, IMHO, 3-3-94 as a "all around" shooting alloy, economocially speaking seems the best way to go.
.
see the 8th paragraph titled: Multi-component alloys
http://www.lasc.us/Fryxell_Book_Chap...Metallurgy.htm

[popper]

At low Sb and Sn tp Pb concentrations, when solid, NO SbSn molecules are formed! Just a mixture with very little effect on the alloy. So NO hardening, tin just helps surface tension so better fillout. Cu added to the low SB does harden. Basically, anything less than 2% Sb is a waste.

[huntinlever]

OK, thanks guys. I did read the Lasc alloy materials but to be honest my mind is wired differently and I've forgotten most of it. The only thing I recall is what you're touching on, Jon, the value of equal amounts of tin and antimony.

I need to look more into hardening and alloy composition. That said: let's say I'm undershooting estimated hardness with the sub-% alloy, even with water quenching. That raises the question - how hard needed for whitetail? I've always sought a clean punch, a .45 caliber tunnel, with the 45-70, and figured I was getting around 18 BHN after curing. At 1650 fps or so, though, it strikes me as I'm trying for much higher BHN than necessary. Plain lead after all did the trick for centuries though granted at much slower velocities.

For woods hunting whitetails, isn't hard cast a bit unnecessary?

[Bigslug]

You're running some pretty toasty numbers in your .45-70. Personally, I'd be looking for BHN's north of 12-14. Straight Lyman #2 at 15BHN allowed to air cool should be just about ideal, though you could go harder by diluting 50/50 with lead and then head treating. The straight AC #2 approach saves you a certain amount of that pesky age hardening/softening.

While 10 BHN makes a nice mushroom, I've found the accuracy deteriorates rapidly above 1200-1300 fps - at least when using a 20-1 lead/tin binary mix and a plain-base bullet design. You've got a sizeable meplat and you're going for speed, so mushrooming isn't needed and bullet rigidity on takeoff is desirable - go harder.

[huntinlever]

You're running some pretty toasty numbers in your .45-70. Personally, I'd be looking for BHN's north of 12-14. Straight Lyman #2 at 15BHN allowed to air cool should be just about ideal, though you could go harder by diluting 50/50 with lead and then head treating. The straight AC #2 approach saves you a certain amount of that pesky age hardening/softening.

While 10 BHN makes a nice mushroom, I've found the accuracy deteriorates rapidly above 1200-1300 fps - at least when using a 20-1 lead/tin binary mix and a plain-base bullet design. You've got a sizeable meplat and you're going for speed, so mushrooming isn't needed and bullet rigidity on takeoff is desirable - go harder.

So, the second option is what I'm actually doing - 50:50 lead:No. 2, then water quenching. I'd thought that would get me around 18 BHN, which I'd thought not too soft, but not so super hard I'd risk break up and that much more meat damage. But if I understand correctly, the estimated 1.67% each of tin and antimony at this ratio, the water quenching won't do much?

I have to say - and I know in terms of any hard data, this means nothing - but these mature bullets seem pretty dang hard. Not sure how to use non-technical hardness testing.

[JonB_in_Glencoe]

My first thought is, a 425gr boolit leaving the barrel at 1650+ fps is overkill TIMES TWO for whitetail deer.

[JonB_in_Glencoe]

My opinion is to slow down the load and don't use a water quenched boolit, I don't think you need anything harder than your 1.67-1.67-96.7 alloy boolits that are air cooled.

If you can't figure out an easy way to cast without water quenching, you can anneal them.

If you are curious if your 1.67-1.67-96.7 water quenched is really harder then annealed, you could try the testing via the pencil method.
https://castboolits.gunloads.com/sho...s-with-pencils

If the pencils don't work for you, I'd anneal some of your water quenched 1.67-1.67-96.7 boolits, Then just do a simple vice squish comparison, to see if an annealed boolit squishes more easily than your water quenched.
Good Luck.

[JonB_in_Glencoe]

SNIP...
But if I understand correctly, the estimated 1.67% each of tin and antimony at this ratio, the water quenching won't do much?

To be clear, what I said was, "Lead alloy has less than 2% Antimony... doesn't respond as well to water quenching"
To be honest, It's hard to say how much it will harden. That's something you need to measure with your specific alloy and your casting technique...btw, water temp matters a lot...add to that, as water temp warms up as the cast session goes on, the hardness will be reduced, so you can have variance within a batch cast in the same session.

[huntinlever]

My opinion is to slow down the load and don't use a water quenched boolit, I don't think you need anything harder than your 1.67-1.67-96.7 alloy boolits that are air cooled.

If you can't figure out an easy way to cast without water quenching, you can anneal them.

If you are curious if your 1.67-1.67-96.7 water quenched is really harder then annealed, you could try the testing via the pencil method.
https://castboolits.gunloads.com/sho...s-with-pencils

If the pencils don't work for you, I'd anneal some of your water quenched 1.67-1.67-96.7 boolits, Then just do a simple vice squish comparison, to see if an annealed boolit squishes more easily than your water quenched.
Good Luck.

Thanks. I'll try it. I hear you on the water temp changing, and am probably just way off on estimations. Creature of habit and "it worked before," took many deer, and I've just stuck with it. As I say above, I'd love to find something mid 1400's or so that is hunting tight enough (for me). So far not found that.

[huntinlever]

To be clear, what I said was, "Lead alloy has less than 2% Antimony... doesn't respond as well to water quenching"
To be honest, It's hard to say how much it will harden. That's something you need to measure with your specific alloy and your casting technique...btw, water temp matters a lot...add to that, as water temp warms up as the cast session goes on, the hardness will be reduced, so you can have variance within a batch cast in the same session.

OK, thanks. Wondering if I should just simplify everything, go to 3-3-94, and be done with it. Looks like enriching my existing blend at 1:1.5 No. 2: (1.67-1.67-96.7) will get me that 3-3-94.