High Copper Alloys- Lets discuss this further

[TheDoctor]

As I have stated previously in other posts, I am not a rifle caster. However, I am now going to be helping a friend of mine with his 300 Blackout. He wants to shoot high speed, and heavy subsonics through a suppressor. Also wants to shoot hollowpoint and solids for hunting. Mainly for hog. Playing around with the lead alloy calculator, I came up with this:



The idea was to keep the copper down to close to .1%, and not let the antimony content exceed that of the tin. At least in my head, by what I have read, and trust me, just on this site there is a LOT of reading, that it should make a fairly tough, yet malleable bullet. Hardness might have to be increased quite a bit for shooting through a rifle. I have pure, lino, foundry, range scrap, COWW, SOWW, 50/50, 60/40, 63/37, #2, and the solder listed to play with.

The plan is to also ESPC the boolits using a 315 degree cure polyester coat.

Now, for the kicker. We currently do not have any molds to test this with yet. If the calculation looks correct, or if someone has something in mind that will work better, I am always open to better ways of doing things.

The custom alloy I have listed on there is from some solder wire I have that I had analyzed.

If someone would be interested in testing this solder as an additive, in an attempt to meet the requirements stated above, I can send 2-3 pounds to them, but please, do not waste my solder if you want it. I have a decent amount of this stuff, but it is a finite supply. Once it's gone, it's gone. Accurate posted results would be expected as the price, but any left over would be yours to keep, of course. For what I can tell, a little bit of this stuff will go a long way. Thanks.

[Whiterabbit]

OK, for those of us who just want to sit on the shoulders of giants and move on (aka directly benefit from YOUR hard work), what's the recipe?

I buy a few #3 babbit ingots from Rotometals. How much lead do I mix it with? Do I need anything else?

Just mix with lead till the Cu is 1%?

[felix]

Good on you, Popper! Thanks, for the experiment which shows what we are looking for: Cu does, or does not, affect HT applications. Copper is showing its independence as expected. Copper is pretty far away from our more natural boolit elements on the Atomic Chart. ... felix

[Whiterabbit]

OK, for those of us who just want to sit on the shoulders of giants and move on (aka directly benefit from YOUR hard work), what's the recipe?

I buy a few #3 babbit ingots from Rotometals. How much lead do I mix it with? Do I need anything else?

Just mix with lead till the Cu is 1%?

4 lb super tough, 1 lb super-hard, 24 lb lead yields 3%Sb, 1% Cu, and a ton of tin@ ~11.5%. Cost is $200 or $7 a pound. 168 grain bullets would cost 22 cents a pop after GC and lube, and 850 grain BMG bullets would cost 90 cents a piece.

hrm.

[TheDoctor]

Wow, seems that this solder actually would be useless for this application. I was thinking that since the copper was already alloyed with the tin, and since tin is easily alloyed with lead, that this would be an easy way to get a lead/tin/copper alloy. Sometimes my thinking IS way off, but I will be the first to admit that I know little about metallurgy.

[Whiterabbit]

so, if I have no desire to tin copper wire and add it myself to my melt, what alloy of pre-mixed copper do I use that can get me some tough casting alloy? When it comes to tin and antimony, "the work is done for me" and I can use linotype, solder, or any number of alloys out there to "sweeten" my lead with Sn and Sb. What alloy is out there that I can use to "sweeten" my lead with copper?

[felix]

That's why slow speed babbit is made with lead as the base material and not tin. Shear strength. ... felix

[badgeredd]

0000000

[badgeredd]

tyuio

[badgeredd]

vvvvvvvv

[felix]

Yeah, I can understand it, but prolly not comprehend it to the extent necessary to play with it in the "lab", my basement pot having no required measurement devices. Just too many elements to second-guess (via intuitive second-nature) the eventual composite into a desired boolit for a definite purpose. Keep up the good work. I can forsee both you and gear leading others in compiling a book for castpics: Alloys and Lubes, to append the excellent comprehensive work done by Glen Fryxell. ... felix

[Larry Gibson]

popper

My limited experience with Cu in the alloy is based on Edd's suggestions. I also push those bullets (311466 & MP 311-180) to 50,000+ ps and maintain very good accuracy. The bullets, especially when WQ'd are extremely hard (30- 35+ BHN). I also would like to know how the tin "weakens" the alloy? I also know that these alloys, even when cast hot do not fill out the moulds as well as standard "balanced" ternary alloys. I wnder how much further th reduction of tin will cause less fillout and rounded drivin bands?

Larry Gibson

[meeesterpaul]

An interesting thread. Here are some recent scans of letterpress that has Cu content. I don't have a hardness tester to test the BHN of these samples but thought I would post for general interest's sake.
I'm looking for the alloy and lube combination to use for speeds relevant to 38 Super and .30 cal rifle. I'm sure there are comments on this site but I welcome suggestions or links.
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[meeesterpaul]

Popper,

In what way does the Sn "weaken" the alloy and what are the effects of the perceived weakness in bullet alloy (not solder)?

Edd

btw; I have some old letterpress that shows an alloy of CuSnSbPb. Anyone want to test any samples for structural issues?

[KYShooter73]

How much zinc would you recommend per lb of COWW using the CUSO4 method for a speedy .308 boolit? I got some nice sounding "tinks" dropping my last batch in the bin after water quenching, but lost several pounds of "oatmeal" in the process. Added 52 pennies to 18lb COWW, 1%tin, and as much copper sulfate as it would take. I assume I either did my math wrong or didn't have enough heat.

[KYShooter73]

That's what I had....silvery oatmeal. Thanks.

[badgeredd]

fffffffff

[badgeredd]

whatever

[Nrut]

From Felix's chart.

Whatever!

But there is no SuperHard Babbit as you call it on Felix's chart.
There is however Super Tough..
Is that what you mean?

If you mix Pb in any ratio with Super Tough (#3), no way are you going to balance Sb & Sn..

[badgeredd]

mmmmmmm