Seating primers correctly can be frustrating. Using the primer attachment on a Rock Chucker didn't always get the primers seated correctly for me, no matter how much oooomph I put into it. Primer Pocket Uniformer solved my problem with 38 Special brass.
With the RCBS hand priming tool, I can squeeze the handle till it will go no further (use both hands) and sometimes (rarely) still have a primer seated too shallow. Perfection is unachievable, in me estimation.