Lead-free bullet casting alloy

[Ian]

Still riding the back side of the learning curve here. I figured 385⁰F was safe to powder coat but it was just a little too much, my ten test bullets all bulged and slumped the bottom driving band.

So I tried again, switching from 400⁰ powder at 385⁰ for 25 minutes to 350⁰ powder at 340⁰ at 21 minutes. Still a bit much, got a tiny drop of alloy squeezing out on the second driving band but I decided to pop them off with a knife, post-size, and test them anyway, just maybe not at 3K fps! Also finger-lubed and taper-sized some with LBT Blue soft to try conventionally.

Going to start this off at about 2K fps and go up from there.

 

[fiver]

19grs of 3031?

 

[CZ93X62]

We are working Ian like a rented mule. It is MUCH APPRECIATED.

That delayed freeze-up phase is reminiscent of making Bruce B Soft Points. The molten metal sounds like it retains its acquired heat jealously, and abhors sharing it with the mould metal's heat-sink properties.

 

[Ian]

So a lot happened, all of it good.

First off I started with 13 grains of RX7 because I love the stuff and it happened to be in the powder measure. Patched out the MVP and shot one of the ones lubed with LBT Blue into the bullet trap. It went two feet into the sawdust and ended up thusly:



Look at that base band and let that sink in a minute.

Then I tried a powder coated one and it went about 3.5 feet based on the paper partitions but I never found it.

After that I cleaned the bore to check for "lead" and it was good.

 

[Ian]

Next I loaded five more lubed with LBT and sent them at 50 yards.

Bottom right was the first shot, then the next up and left of that, then three in one hole. LBT has always done that with this rifle and this bullet, maybe I'm filling too many grooves?

Ignore the elongated hole, the paper was free hanging and curled.

 

[Ian]

I thought that was pretty good so I headed back inside to load five more to shoot at 100 yards and also grabbed the Magnetospeed. I couldn't get a good reading but 2K to 2250 fps were my error options. Again the low right first shot flyer:

 

[Ian]

I gotta take the wife and kids to dinner but it gets better, back in a couple of hours.

 

[fiver]

woah.....
I'm seeing more than just that drive band.
I got like 3 WTH things???? going on there.

 

[Ian]

Yeah, I know. Not sure how much of the accordion effects you see happened in the trap and how much happened in the rifle. The nose did expand somewhat and the bullet slightly bent because it tumbled about a foot inside the trap. The engraves on the front band are longer on one side so it got crooked at the start somehow. It also looks twisted along the engraves, will have to study it some more.

The next group at 100 was boosted up to 15 grains of RX7. However, as I snuggled in behind the rifle, a spike buck walked out at 95 yards right in front of my target and turned to face me. I thought "Are you freakin' kidding me? Well, it's about two hours before dark, still have time to get him in the refrigerator and take the family out for a much needed date in town, I think the two extra grains will raise the POI about two inches, for all I know the bullet will dust in the hide or pencil through to the next zip code, but if I drill him in the heart maybe he won't run too far". So I adjusted the bag and...



Exit side:



Chronograph was indicating 2350 or 2500 fps with errors, take your pick.

He hit the dirt, got up and stumbled about 10 yards and fell over.

After making sure he was dead, I shot these four for a group (barrel had cooled again, you can guess which one was the first):



Three into a little over a half inch, not bad for a rifle that averages 1.5 MOA with everything I've ever fed it. Definitely need to shoot some more groups. Main thing I find encouraging is the lead-free bullets are doing at least as well if not way better than anything else that has ever been down the barrel....including match jacketed handloads....and I've shot nearly 500 rounds of cast through it.

 

[Brad]

That was a 22? If a 22 going that fast does that well then a 180-200 gr 30 cal should be just as good.
Dare we say Ian has proven that a 22 cal lead free cast bullet is very capable of cleanly taking a deer?

Impressive work in a couple days. What are you planning for a follow up next weekend?

 

[Ian]

More on the bullet performance. The deer was facing me but very slightly quartering to my left. The bullet broke the front rib just to the deer's left of center, went straight through the heart, broke up into three pieces, put three holes in the diaphragm and continues on through the liver and guts, making about a 3" spread of holes in the right side loin/skirt. The fragments must have bounced back in the guts because I didn't find any but the gas check was stuck in the hide. There were about three heaping double handfulls of clotted blood in the chest cavity and the guts were all bloodshot but not badly ruptured. Evidently the stomach wasn't hit and the holes in the intestines were small, so dressing out wasn't nearly as bad as I had feared it would be when I pulled the trigger. The only meat I lost was the tip of one of the tenderloins.

Inside of the right skirt steak, two bullet fragments and the gas check penetrated here:



Outside of the skirt steak, me trying to find the fragments. Only found the gas check, and no holes in the hide:



The bullet did really well and all the pieces traveled in a fairly straight line after breaking a rib, blowing up in the heart, passing through the liver and ending up at the hide in the loin. I never dreamed this lead-free bullet could do all that on a deer, but I had the opportunity for a perfect shot.

 

[JonB]

I am speechless !

 

[Ian]

That was a 22? If a 22 going that fast does that well then a 180-200 gr 30 cal should be just as good.
Dare we say Ian has proven that a 22 cal lead free cast bullet is very capable of cleanly taking a deer?

Impressive work in a couple days. What are you planning for a follow up next weekend?

Next weekend I'm planning to eat turkey, venison, and pie and spend some long-overdue time with my wife, kiddos, and wonderful mother in law. Might work on the house too, need to get that siding finished on the addition and also take the family to pick out a live Christmas tree and get that set up.

 

[462]

I've been following this since the beginning, and many times have come close to posting a "Like".
I know as much about metallurgy as I do nuclear weapons* and am not a hunter, but this thread has been educational.
Anyway, Ian, here's another "Like", for you!

*Actually, I know more about nuclear weapons, being at one time certified to load them.

 

[RBHarter]

How often do you get to do terminal impact tests in the middle of load work ups .........
That looks like it definitely did the job well placed anyway .

 

[RBHarter]

I must have missed it somewhere . How did the finish drop compare to designated weight vs what the normal drop weight of the moulds vs actual drop weight ? I'm just curious about how close weight wise the Bisamonin alloy is to say WW or lino or some nominal other .

 

[fiver]

Ian didn't say but i'll say it'll be a bit lighter than lino-type.

remember what I was saying about trying to pre-swage the bullets before use and comparing the crystalline nature of the alloy.
I'm gonna go out on a thesis education ramble prediction [limb] and say your seeing the land thing because the bullet was internally crunching up under pressure and being pushed forward.
that base and other drive bands are confirming the crystalline break down.
the tin is the savior and I have a feeling the Sb is also helping that flow happen.

if you remember the zinc copper alloy Popper was working with before, he was struggling to get something going there and I suggested the addition of antimony to give the copper some place to go.
anyway that started the boundary layer interface [and the very low tin alloy he was using was letting it act as a grain refining agent instead of it trying to be an actual part of the alloy]

I have a thought about using sulpher here, since the 'other' addition we had been kicking around has been kind of bothering me.
it is the only other thing I can come up with except possibly some copper sulphate to gain a bit of both.
only thing is that sulphate would lower the tin content in the trade. [maybe not such a bad thing though with the other additions]
anyway a grain refining agent will get those crystalline structures under more control and probably stop some of that 'slumping'-bumping-obdurating whatever.

oh, yeah,, i'll 100% go with the off side skin kicking the chunks back into play.
skin is super elastic [why you often find a bullet against the offside skin] and I bet it stretched out a good 3 maybe 4 inches when the fragments hit.

 

[Ian]

How often do you get to do terminal impact tests in the middle of load work ups .........
That looks like it definitely did the job well placed anyway .

This makes twice for me in 30 years. Many times I've had to throw a rock to clear a doe from in front of my target, they love to mill about in the shooting lane I cleared through the brush.

On the bullet weight I was at 58 grains fully dressed for a bullet that is 68.4 grains from wheelweights.

From what I gathered from the work the Fujitsu guys did with 57% bismuth solder, silver, and copper both form on the bismuth on the primary phase of crystallization and increase ductility slightly in amounts below 3%. Above 3% they make the brittleness worse. Antimony precipitates out in the form of Sb/Sn intermetallic along the boundaies of the Bismuth crystals after the primary phase (Bismuth) has solidified. This is exactly what copper does in a Pb/Sn/Sb although I'm not sure what sticks to what or when. The little "coating" that the trace metal addition gives to the primary crystals keeps them from slipping and fracturing so easily. The combination of things when they're right will break up the primary crystals as they form and glue it all together like cement does in concrete aggregate. To make concrete stronger and more flexible, add more sand and a little more cement.

Adding copper might help ductility of this alloy but I don't know how it will act with the antimony. If copper and bismuth stick together on the primary phase and then Sb/Sn forms and precipitates out on that and finally tin fills the gaps it might be an improvement.

 

[fiver]

in a lead alloy the copper goes with the antimony but it forms a longer thin film surrounding most of the layer between it and the lead.
if you have tin you have to have a titch more antimony to take up the copper or it tends to go rogue and kind of worms it's way in between the tin antimony bond too.

anyway that copper boundary allows the antimony to break down still but it's kind of bound up by the copper and that's where the toughness comes from when you use it.
the alloy retains the malleability because that's what lead does, it mushes under stress, and the antimony breaking down under stress allows it to flow easier.


this alloy is different so I'm only taking a stab at what will/might/should do what,,based on what it does elsewhere with the same stuff.
either way I think a grain refining agent would help, and it certainly wouldn't hurt.

 

[RBHarter]

About 15% light . That makes the typical 405 , 340-350 and a 180 about 160 . Per lb of alloy you get more bullets but you need a heavier design to get to your numbers , on the other hand you get to shoot them faster on the same charge . So numbers become self canceling .
Then we have to battle the "nodes" and hope we can keep the speed for weight trade off .

Will we need to change bullet design to keep CoP in line with CoB ?

On a more positive note it looks like the small cal deep groove bullet made a fine triple wad cutter on impact and managed light bone .

I didn't study the bullet trap bullet hard but it was mentioned that it appears to be twisted . That would be something to add to the transition ballistics books . I know a guy that's pretty deeply invested in what happens at the muzzle with long contact bullets .