How to mix these two alloys for a 45-70 hunting bullet?

[Petander]

Good day gentlemen.

Years ago I used to mix monotype to WW after I cleaned WW, it was not the best idea but at least I marked the % on the final ingots. I mixed in 10,20 and 30% of mono.

Here is my typical hard alloy, about 18 BHN:



Now, I want to make a short range whitetail bullet, 470 grain WFN 45-70. I also have pure lead from air rifle pellet traps.

My question:

How many % of that high antimony hard alloy would you mix with pure for a "dropper" whitetail bullet? I know I could make the soft nose separately but let's not go into that technique here. I could use a Speer 400 as well,I have shot a few moose with it and it works but... I want to try cast now. Waste shoulders if needed,I need to stop them.

This would be for a location where an instant drop is desirable for several reasons like a nearby swamp and hunting area border.

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The bullet in question is a Robert Applegate 470 grain bullet which cycles in Marlins.



Thanks for looking.

[405grain]

There's a "Lead Alloy Calculator" in the sticky section of this lead & lead alloys forum that might be helpful. Your alloy has a lot of antimony in it (even if you cut it 50/50 with pure lead it would still have a high antimony content). To get an alloy with good expansion characteristics at 45-70 velocities you might need to add so much lead that it dilutes the tin content in your alloy. If that's the case you might need to add a little tin into the mixture to keep the tin content between 1.5% to 2%. The trace copper content in your alloy will contribute some "toughness" to the alloy, which is beneficial. Why there is niobium in your alloy is beyond me. Niobium is a refractory metal with a melting temperature above 4000 deg. F, so it is likely finely divided particles in solution, and not a part of the alloy. It is about as hard as titanium, so is softer than barrel steel. As a contaminate the niobium in your alloy probably has no effect on cast bullets.

Here's some thoughts: Cut your alloy 50/50 with lead, then bring the tin content back up to around 2%. This will give you a good general purpose rifle bullet alloy that's quench hardenable, but is also good as air cooled for most rifle bullets. You can mark ingots of this as "hard alloy". If you want softer bullets for 45-70 or pistol application, you can then cut this "hard alloy" again 50/50 with pure lead. If, when you add lead to your existing alloy to create this hard alloy, you use a pound or two of chilled shot (size BB and above works best) then you will be adding some trace arsenic to the mix, which will act as a grain refiner and improve hardness when you water quench.

The alloy that you have now is rhinoceros hunting hard, but can be used as a base for making some useful alloys. A final thought about expansion with your loads; a .458" diameter bullet is already at a diameter that many other hunting bullets expand to. It's already big, and it's not going to shrink. With that in mind, so long as the bullets aren't brittle, loading for accuracy will have more effect in a successful hunt than expansion will with a bullet that's this large.

[RickinTN]

Wheel weights mixed with pure at 50% each plus about 2% tin. Keep your tin and antimony to equal parts. I'm not sure how to get there from where you are but this is where I suggest you end up.
Good Luck to you,
Rick

[Rockindaddy]

Great topic for discussion! Have shot a lot of deer with cast boolits over the years. Many a whitetail have fallen to my 45-70's and 50-70's. I never recover a bullet out of a deer. Usually they are shot through. Have found that soft boolits work to my advantage. You get tired of trailing a nice buck that was shot through. I have trailed them with a broken shoulder and ventilated lungs. They just keep moving. Sometimes getting to the opposing ridge only to have another finish off my trophy and claim him for his own. Shot a nice buck several years ago with my old 50-70 Sharps rifle. Could not figure why he didn't drop in his tracks. After a second shot the old roe finally fell over. When hanging, back at the barn and all skinned out I found two holes 2" apart. One through the heart and the other just cutting the side of the heart. Then I went and looked at my ammo. I had been shooting hard tin/antimony bullets!!! Dummy me. Since, I use 1:20 tin - lead alloy. The bullets mushroom and deliver the energy where they are supposed to instead of passing through the deer's torso. This lead tin does not lead the bore. Lead pipe and line sheathing is dead soft no alloy lead. The joints on lead pipe are tin. Use the joints to alloy the lead mix.

[popper]

Yup, just hard enough for 50 yd accuracy and not splatter when/if hitting bone. For that purpose, tin wil have NO effect. I assume fps is about 12-1300?

[35 Rem]

I agree with downloading a copy of the Excel spreadsheet for alloys that can be found on this forum in several places. It will let you experiment with any combination to see the results.

That alloy you have has so much Antimony that you will need to buy some Tin if you use it with WW's to keep the Antimony/Tin levels proper for hunting bullet performance. I've had great success with the 50/50 Clip-on-WW/Pure lead plus 2% Tin alloy that so many on the forum use for rifle hunting bullets. They give great expansion and retained weight with minimal leading. Velocity of my loads are all between 2,000 and 2,100 ft/sec.

[JonB_in_Glencoe]

IMHO, I would suggest to drop that 12% Sb to about 2% or so.
So that would be something like 4lbs of soft with 1lb of Hard alloy.

to better answer this question... 20%

How many % of that high antimony hard alloy would you mix with pure

...and yeah, you should probably add a bit of Tin

[BLAHUT]

For me, I just use pure lead, 500+gr, at 1200 FPS, in my 45/70s, I just melt down the pellets and cast my bullets. Bear or deer drop in there tracks.

[Larry Gibson]

Another here for no antimony at all. Mix the pellet lead with tin at 16 parts lead to 1 part tin.

[Good Cheer]

My brother shoots 500 grains of straight lead in his at 1800FPS.

[Petander]

Thanks for all the replies.

I'm reading Taylor's book again. I'm probably going to make a very low antimony alloy for this. Add tin yes.

[Petander]

Some molds have a Hollow Point option. I have a Mihec 458 400 grn with HP pins.

With pure lead,I wonder would a HP make the bullet a total "Devastator"? My 470 NE practise load has a HP option too. 400 grns @ 2100 fps.

[Wilderness]

Petander - you might consider checking or controlling your alloy/hardness by going on bullet weight.

If you know the weights from the alloys you have on hand, and know where you have to end up, then a bit of simple maths will get you the proportions required. For instance, if one alloy casts 480 gns and another 440, then a 25/75 mix will give you 450 gns. Tin and antimony being of very similar density, and both being less dense than lead, the weight method will get you the % non-lead (tin and antimony combined) in your alloy, but not the specific amount of each. At the proportions found in say linotype, some antimony/tin substitution will not throw out the hardness calculation by much anyway. With a bullet of around 450 gns, according to Lyman data, a 1% change in non-lead will get you about a 2 gn change in bullet weight.

The same method will work if your harder alloy is a straight lead/tin mix of unknown proportions.

A starting point would be to cast some test bullets from a known metal, e.g. your softest/pure lead. Make 20 or 30 so you get enough good ones for an accurate assessment. Do the same with the hardener, if you do not already have this weight. Then do your maths, mix, and assess the result on the 2 gns/1% "rule".

As for what the target weight/hardness should be, you will depend in the first instance on the answers you get to your post. Once your animal testing tells you the alloy is right, keep going back to that weight.

Last point, label the leftovers from the casting session with the bullet weight for future blending or adjusting.

[Petander]

Wilderness,that's a good idea thank you.

My sample sizes were small here, that's why my weight difference % varies with mold/bullet. 3-5% is too much to be true, pure is tough to cast.



EDIT: I took similar samples of 20 bullets. Hard alloy average weight was 451 grains vs 467 grains of pure. So my pure bullets are 3.5% heavier than my hard ones.

[mnewcomb59]

Well with that small of a difference in weight I don't think your hard alloy is 12% antimony, OR your pure lead was not very pure. If so you probably would be around 450 grains hard and 480 grains soft. Your bullets are roughly 3% different in weight when you would expect around 6% lighter if your alloy really was that rich. Judging by the weight difference (if you had some really pure lead to compare your heavy bullet) your hard alloy is probably around 6% antimony.

[Wilderness]

My .30-30 bullet weights don't quite line up with the Lyman prediction either - 164.5 gns with my "Linotype" and about 178/179 gns with my softest material (cores of jacketed bullets, .22s, roofing lead etc), for what is supposedly about a 15% difference in non-lead. My lino might be harder than it is supposed to be. And yes, the bullet weights for the "soft" alloy are more approximate because it's harder to cast good bullets from soft scrap.

The bottom line however is that once you have a weight that works for hunting, in my case 170 gns plus or minus about a grain (hollow points), you can keep going back to that weight regardless of the truth of your original assumptions on constituent alloy compositions. And you can label any new mystery alloys on bullet weight alone, and blend with it accordingly.

[Petander]

I should XRF my "pure" before making assumptions.

I do assume that my hard alloy XRF is correct. Gotta trust something. Niobium is the stranger there, it is the contaminant that interferes with Hi Tek coating. I clean my bullets in muriatic acid before coating with Hi Tek. Only then I get proper bonding.

No Idea where niobium came from but it is everywhere in my WW based alloys.

[Deadeye Bly]

I agree with others than a hunting bullet should be a softer lead, perhaps 25/1 or 30/1 lead tin with no antimony. That big meplat will do a lot of damage but if it expands to 5/8" or 3/4" diameter it will do more damage. I've recovered very few soft round balls from deer. They generally pass through. The 50 caliber ones that hit bone directly that I've recovered were about the size of a quarter.

[Petander]

I did a 10/90 mix of my hard and "pure".

Saeco tester reads 6,5 BHN, my assumed pure reads 5 BHN.

At least this is not brittle like my 16+ BHN stuff, HP smashes away when those bullets hit something.

EDIT: I smashed these with a hammer after coating. I may try 20/80 hard/pure next, these weigh only a few grains less than pure ones. I will also add tin for better fillout.