The key with the hammer type inertia pullers is what you are hitting them against. They work well when whacked against something very solid and dense. Mine is uselss on top of my reloading bench table top, but works great when I whack it against the side of the table top. If I get a really stubborn one, I have a 3"x4" piece of metal a half inch thick, and place it on a concrete floor, and whack on it. (don't hit the concrete with the plastic hamer) The anvil part of a vice works great also. Most wood soaks up too much of the energy of the strike.
I scratched my head on that one too.
I scratched my head on that one too.