I have noticed that until I get my Lee 6-cavity mold HOT I have trouble with getting the bullets to drop. So, I tend to beat on it with an 1-inch thick oak dowel. Typically I try and hit the handle nut.
But, when I get frustrated I take a gentle whack at the edge of the bullet. So, of course I just had to remove a burr from the edge of one of the cavities, and will probably be stuck with a tiny wing on bullets from that cavity.
Wish I had thought more before hitting.
Since the mold seems to work great when it is hot (e.g. I have to wait for the sprue to harden) I think I will be getting a hot plate to better pre-heat the mold.