The only real problem I have had with a Lee six cavity mold was with my very first group buy mold. I had waited until the warranty period was over before even trying it (waiting on funding to buy handles). I kept getting out of round boolits- .314x up to .321, with the occasional round ones.
I tried everything I could think of or read about. Finally I was going to introduce it to my farriers rasp to try to get round boolits, when I noticed the alignment pins were slipping and had kind of peened the edge of their hole outward.
Being just a bit vexed at the dang thing by this time, I trimmed the offending aluminum with my pocket knife and staked the pins in place. Ugly, but it worked. I now get .314x.314 boolits from that mold every time, unless I put pressure on the sprue handle of course.
Robert