Did you follow the cycling procedure outlined by Al in the instruction sheet?
Are you using a hotplate to bring the mold up to temp before casting?
What is your alloy temp?
Are all 5 cavities sticking?

Jerry

To the best of my ability, yes.

I wasn't using a hotplate the first time but I just tried it and it didn't help. The problem isn't relegated to the first few casts anyways; I'll cycle the mold 50 times and it'll happen every single time.

I don't have a thermometer but I use a Lee 4-20 pot and have the temperature set as high as it will go, so probably around 800+. This is the only way I can get complete fill out with this mold, and even then I still get rounded edges sometimes. None of the bullets ever come out frosty. I am casting as fast as I can, but obviously having to whack the mold 40 times to clear the bullets slows things down a bit.

Yes, all five are sticking; I have not noticed any particular cavity that was noticeably worse than the others.

Also, I'm using an alloy of 50/50 Linotype and COWW with a bit of foundry type thrown in.

This is absolutely baffling to me.