Possible zinc contamination?

[45acp]

Hi.
Today when i was going to cast some i got some boolits that had some strange faults.

I have recently melt down some ww and i wonder if there might have been some zinc weights in there?
I hope this might been caused from another reason.
Not all bullets, maybe 30% has some faults.
No wrinkles that i understand is common with zinc contamination.
I had the same temperature as i use to (arond 703F, pid controlled).
The only thing that i can think about is that i heated the mold a bit hotter before casting, (and maybe dropping them a liitle faster than usual.
What do u think? Will i need to dump my muffins, around 180lb?
https://imgur.com/nsz3pIY
https://imgur.com/cD0yWkX

[lightman]

Have you used that mold before and gotten good bullets? Did you have a slushy oatmeal looking stuff floating on top of the molten lead?

[45acp]

Yes, used before and got excellent bullets.
Nope, melt looks fine i think, hard to tell since there are very few movies that shows that slurry oatmeal.
Looks kind of brittle when cooled down in pot after finished session.

[modified5]

A drop of muratic acid would tell the tail.

[45acp]

Got my answer,,, no zinc.
Thanks!

[jimb16]

Add some tin to your mix. That will likely cure your problem.