Zinc

[Lead Freak]

Ok, I'm confused. I understand how zinc contamination can cause casting issues (boolits not filled out, frosty boolits, irregular hardness, etc.), but if you maintain a reasonable hardness, why would they damage your bore? I have a batch of WW lead that I believe may have some contamination, only because the boolits consistently measure out at 22bhn rather than the 12-13bhn that I would normally see with WW alloy. While a hard alloy that may need to be reserved for hotter loads to match the boolit strength, why would this alloy damage the bore even if there is some zinc contamination? :confused:

[Lizard333]

Check that you have zinc in your allow by putting a couple of drops of muratic acid in a sample. If it fizes a lot, you have zinc. I believe anything less than 2% zinc in an alloy is ok.

Yesterday I was smelting COWW and I use a turkey fryer burner and a torch. I hand sort my WW's but apparently I let a zinc one get by. I had two hundred pounds of COWW in the pot when I noticed one of the WW's not melting. Sure enough, zinc. Well, a small part of the WW melted. This small amount in two hundred pounds didn't make a squat of difference.

How are you cooling your ingots? If you are cooling them quickly, it can effect your hardness. 22 sounds like water dropped COWW.

[runfiverun]

zink won't hurt your bbl.
there have been molds that take zink washers as gas checks, and molds made specifically for zink boolits.
at one time there was a line of bullets called "jugular" that were zink,they got quite a bit of press in the magazines because of the high velocity's that could be obtained with the lighter bulets.
was in the late 50's maybe early 60's airc.

[Defcon-One]

I agree, Zinc will not hurt your barrel/bore. Not even pure Zinc will, and you are talking about a Lead alloy with just a bit of Zinc contamination in it.

If you can cast it into usable bullets, I would say that you can shoot it without any worries.

Now casting Zinc contaminated lead into good quality, usable, bullets is the hard part!

[I'll Make Mine]

The problem with zinc isn't bore damage, it's getting out of balance boolits that may fracture on impact at the boundaries between lead-with-zinc and zinc-with-lead -- because the lead and zinc absolutely will not stay mixed. Heat up some water, pour in some melted butter, whiz to your heart's content in a blender, then toss the lot in the freezer; I guarantee you'll be able to separate the butter from the ice with ease once it's all solidified, and the same thing happens with lead and zinc. When this happens in a mold, there isn't time for full stratification, so instead you get chunks of high-zinc (which freezes first) embedded in the low-zinc alloy -- and bullets that will spin off center because those chunks aren't evenly distributed.

The end result is bullets that will work safely and won't damage your barrel, but will be inaccurate. The simplest solution is to pour the contaminated melt into a single deep container with enough draft and smooth enough surface to be able to remove the entire ingot when it's hard; once it's cold, you should be able to separate the lead-with-zinc from the zinc-with-lead (the latter will be on top) at a pretty distinct parting line. The bottom will still cast decent boolits; the top can be recycled or used to cast light-for-size bullets (but should be kept separate from lead alloys, and probably best not cast in aluminum molds due to the higher working temperature).