Contaminated lead?

I’ve been casting my own round balls for probably 20 years and not had this problem before. Usually my .490 and .440 ball load easily with my short starter and ramrod. This last batch I had to hammer down the bore. I tried a thinner patch but that didn’t help. Is it possible that some wheel weight lead got mixed in? I’m using the same molds I always have. I switched from the small electric pot to a bottom pour a while back but I don’t see how that could make a difference. I can make a mark across my ingots with my thumbnail. How do you tell the hardness of lead without a tool?

Could be your alloy. Do you use range scrap?
Are you sure your mold blocks are closing fully?
Lee molds have a tendency to drop a few thou oversize for me.

sequoia said:

I’ve been casting my own round balls for probably 20 years and not had this problem before. Usually my .490 and .440 ball load easily with my short starter and ramrod. This last batch I had to hammer down the bore. I tried a thinner patch but that didn’t help. Is it possible that some wheel weight lead got mixed in? I’m using the same molds I always have. I switched from the small electric pot to a bottom pour a while back but I don’t see how that could make a difference. I can make a mark across my ingots with my thumbnail. How do you tell the hardness of lead without a tool?

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Did you weigh them?
Balls of a given caliber are of a known weight. If they are much lighter, you have something else mixed in.
That something else might not shrink when it cools the way lead does.

There is a ball size to weight chart in section of tables and useful info near the top of the forum.

Mic the balls see what they measure at.

Saying where you got your lead from will help out answering your question.

Research testing lead hardness with artist pencils, available from office supply places or craft stores. That's the cheapest way possible to get a fairly accurate measurement and a lot of people do that.

The next cheapest way is a Lee Hardness Tester, but you need a centerfire reloading press to use it. There are other ways; more expensive tools, or tricky ricky fabricating your own tool. Soft lead will be in the 5 or 6 BHN range. Dead soft is 5.

It doesn't take much tin to make things a little harder. If there has been zinc added (from the wrong kind of wheel weight) your batch is junk. If you have much good wheel weight metal at all in the mix the hardness is going to jump pretty high and a fingernail might not scratch it.

Being able to still fingernail it suggests tin to me. You may need to get a smaller mold if you can find one. My Lee 490 mold casts big and loads hard with ANYTHING but dead soft pure 5 BHN lead.

I recover bullet cores whenever I run across junk bullets that would be the same thing as common "range scrap". It's a touch harder than dead soft pure lead and tests around 7BHN.

And just a note about testing ingots. Ingots cool at a different rate than bullets, so it's best to test bullets to get the accurate hardness.

range scrap and shotgun shot often have anitmony in the alloy to harden it up.

dave951 said:

range scrap and shotgun shot often have anitmony in the alloy to harden it up.

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Definitely shotgun shot contains antimony.

But as you can cypher from this chart, which isn't gospel but it's righteous enough, you have to get way beyond average range scrap to find much antimony. Unless your range scrap is mostly wheel weight cast or harder of course.

I've tested enough bullet core metal to never have seen above 7 BHN, so almost no, or none, antimony content. Tin yes, antimony, no.

Any whiskers forming on the bullets? Sometimes you can get a splash of lead on the mold block face and it won't close all the way

sequoia said:

I’ve been casting my own round balls for probably 20 years and not had this problem before. Usually my .490 and .440 ball load easily with my short starter and ramrod. This last batch I had to hammer down the bore. I tried a thinner patch but that didn’t help. Is it possible that some wheel weight lead got mixed in? I’m using the same molds I always have. I switched from the small electric pot to a bottom pour a while back but I don’t see how that could make a difference. I can make a mark across my ingots with my thumbnail. How do you tell the hardness of lead without a tool?

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Don't force them just get a bigger hammer.

The Appalachian said:

Definitely shotgun shot contains antimony.

But as you can cypher from this chart, which isn't gospel but it's righteous enough, you have to get way beyond average range scrap to find much antimony. Unless your range scrap is mostly wheel weight cast or harder of course.

I've tested enough bullet core metal to never have seen above 7 BHN, so almost no, or none, antimony content. Tin yes, antimony, no.

View attachment 301089

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You are correct and I've seen many black powder shooters melt down shot and wonder why the bullets are soooo hard.

The easy way to determine softness is to use a set of Stadler artist pencils. They are varying hardness and depending on which pencil will scratch the lead, will yield a pretty accurate Bn figure. Note also that just switching from pure lead to WW can lead to the very issue the OP is experiencing. It's also death on accuracy for minies.

Must have some tin or antimony in the pot. Even a small amount can make the lead noticeably harder.

*UPDATE*
I cleaned out my lead pots of all the contaminated lead. Then I melted down the scrap lead that I got from a roofing company. It’s old flashing from around things like chimneys. It’s very soft and you can write your name on with your fingernail. I cast up a bunch of .490 and .440 balls to use at Rendezvous. Things went much better at the shoot. I didn’t have to hammer the ball down the barrel and I was actually hitting a bunch of targets. I still have another 10-15 lbs of this lead to melt down eventually. Now I have to determine how contaminated I still have.

dave951 said:

You are correct and I've seen many black powder shooters melt down shot and wonder why the bullets are soooo hard.

The easy way to determine softness is to use a set of Stadler artist pencils. They are varying hardness and depending on which pencil will scratch the lead, will yield a pretty accurate Bn figure. Note also that just switching from pure lead to WW can lead to the very issue the OP is experiencing. It's also death on accuracy for minies.

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I like my Lee hardness tester because it gives me a number I can write on the box containing the lead or lead alloy. I like numbers to define what I have. I've never fooled with the pencils but I see a lot of folks do.

Pure lead WILL be scratched (rather deep) by the corner of a thumbnail dug into into it. Any alloy beyond pure lead might leave a slight mark if the tin and antimony is extremely minimal, but you won't dig in like you will with pure lead. The higher the tin and antimony content its likely you can't even mark it with a thumbnail.
Another easy test is to simply drop it on a hard floor or a piece of metal. Pure lead will produce a dull thud sound, any alloy with tin and/or antimony will produce more of a ring. The harder the alloy, the sharper the "ring" "ping" sound.

sequoia said:

*UPDATE*
I cleaned out my lead pots of all the contaminated lead. Then I melted down the scrap lead that I got from a roofing company. It’s old flashing from around things like chimneys. It’s very soft and you can write your name on with your fingernail. I cast up a bunch of .490 and .440 balls to use at Rendezvous. Things went much better at the shoot. I didn’t have to hammer the ball down the barrel and I was actually hitting a bunch of targets. I still have another 10-15 lbs of this lead to melt down eventually. Now I have to determine how contaminated I still have.

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I probably know somebody that'd be interested in your "contaminated" lead if you want to get rid of it.

I would be curious if it was a sizing issue vs a hardness issue. Different alloys will shrink more or less depending on mixture/purity. While I haven’t cast bullets or balls, I did cast several thousand pounds of fishing weights over a couple year span as a small side gig weight producer. I always noticed my pure lead casted much better than dirty mixed lead. Came out of the molds much easier. I always assumed the purest lead maybe shrink a bit more than the unknown alloys/contaminated stuff.

Melting points change with lead too, dirty mixed stuff needed to be poured much hotter than the good stuff.