Originally Posted by M27
assuming that all other parts of the process are correct and the problem is with the primers
is that the primer may not sat all the way down in the pocket. if you think about it, the anvil of the primer needs to be touching the bottom of the pocket. Do you think yours are.
how have they been stored, have they been kept dry?
I agree, it sounds like you are not getting them fully seated with the hand primer.
Where they sit relative to the surface of the case head isn't important (as long as they are not sitting proud). What is important is they are fully seated into the pocket, this is what pushes the anvil up against the inside of the cup.