Is it safe to say wrinkles in your cast bullets are primarily caused by lead temperature, and or not having your mold not hot enough? I think I?ve narrowed it down to my mold temp, but are there other things that could cause this?
Thanks

Two thinks can cause the wrinkles...
Oily mold, clean it with carburetor or brake cleaner and then cycle the mold several times to burn off any residue.
Colder alloy or mold can also cause wrinkles, run hotter alloy or pour & cycle faster to maintain temps

Thanks, I did clean the mold with alcohol, lubed the pinch points with bees wax, and cured the mold with a wooden match. I?ll look more closely at the temp next try around

Wrinkly bullets and new casters go hand in hand.  Here is what I have observed both from teaching new converts in person and reading forum posts.

First, the mold needs to heat more than you probably heated it.  I get my 10 lb pot up to about 650 and then set the mold on the top in such a way that the back edge of both halves are in the lead.  I just let is sit like that for 2-3 minutes.  If you pick up the mold, and the lead underneath is solid from having the mold on it,  the mold is too cold.  The challenge is the difference between too cold and too hot is not a huge difference, so sometimes I end up with sprue's that take several minutes to cool in the first pour.

You can also heat a mold by casting really fast.  But new guys will dump their bullets and then look at them with the mold both open and empty.  As soon as the bullets drop, get the mold closed and hot lead back in in the cavities.  As soon as the sprues are solid, cut again, and repeat as fast as you can until you start to see a sprue smear.  Then you can fill the mold, and let it sit for 45 seconds to a minute while you look at your bullets.

Finally, wrinkly bullets shoot fine.  But, bullets with rounded bases from incomplete base fill out do not.  Every time I open sprue cutter but before I drop the bullets I take a glance (less than 1 second) at the bases.  Any bullets that do not completely fill the mold at the base get put back in the pot.

Last Sunday I spent about 2.5 hours on the back deck casting.  I ran about 500 each of 125 grain .358 SWC, 200 grain .400 WFN and 210 grain 452 SWC.  I hope to do the same again this Sunday.

Thank you, this is some very helpful information

When I cast 38s.. it was always the mold not hot enough.
As mentioned, the solution for me was the first few batches just later went back into the melt pot  till the mold heated properly

Like the idea of sitting the mold on pot.

So for keeping the mold temperature up, I?ve read that some use a hot plate and having good success. Is this a viable method, or are you better off just setting it on top of your lead pot?

Hey Kenk.. The alloy you are using hasn't been mentioned..  If there isn't enough tin in the mix you have to run the mold much hotter to get a good fill out. What tin does it reduces the surface tension of the alloy so you get a complete fill out at a lower temperature. Are you using a cast iron mold or an aluminum mold? Some subtle differences in technique between to two. If you are using an alloy with at least 5% tin, then heat, and or an oily mold, is most likely the issue.

Thanks RDub01, I had 2 or 3k cast .45 acp bullets from Missouri Bullet Company that I haven?t load up in a while, so I made ingots out of a thousand of them, and believe they are 18 BHN. As for tin content,  I?m not sure the percentage Missouri uses. As for molds they are Lee aluminum molds

That alloy will be fine!.. Another topic we didn't cover is fluxing. I'm going to assume you know about that...

Yep, I?m using sawdust and or beeswax

My brother-in-law told me today he has a bunch of lead he wants to give me (his grandfather used to make sinkers) Looks like my lead source problem just went away for awhile 😀