I've learned that sometimes a hand sledge works best if I just forget what it is and swing it like it was a dead blow hammer with slower and more methodical swing-through. Especially for things like kingpins, using a dead blow type swing often can get me more success than setting it down and smacking it as hard as I can. And even things like rock work...splitting rocks for example...this approach seems to yield cleaner cuts with less chips and doesn't mushroom the end of the chisel nearly as much. Just a suggestion.
Good luck with the press.
