Guys, I had been having the most awful time with leading in the barrel of my Sig 9mm with cast bullets that I had Hi-Tek coated myself. Bullets were passing the acetone and smash tests. I could not for the life of me figure it out and then I stumbled across the whole 9mm-case-swaging-bullets-down explanation. I had my EUREKA! moment. I posted a question about it in the Reloading Equipment section last week.
Sure enough, my bullets were getting swaged WAY down at the base and this appears to have been accounting for most or nearly all of the leading I was experiencing. I have a Lee Universal Expanding Die and NOE plugs on the way, but while waiting on those, I just backed my decapping/resizing die out a few turns where it wasn't resizing as drastically, loaded some rounds and VOILA!!! Fired 100 today without a sign of lead or Hi Tek left in the barrel.
Thank you to those who commented last week on my question and for this forum in general. Lots of knowledge here. Hope this post helps someone in the future.