Here's a couple I've done reciently so you can get some idea how the traditional "spud" in a HP mold works and some of the options you may have.
"Devastator" in .358
Same mold fitted with an adjustable pin (sleeved to decrease pin diameter and give a little extra integrity to the nose). Pin can be adjusted to the rear lube groove for deep-cavity HP or backed out to nothing more than a dimple in the nose. (not the type of thing that happens at the factory, however)