Brad
I turned an ash handle for my slick. It was not kiln dried but was air dried for a year. When I finished the taper I left it a little long, just in case it shrunk at all in diameter. I like to take mine apart so it fits in my Timber Framers chisel roll. It is a friction fit. Push it together , then give it a tap on a chunk of wood (handle down, use the weight of the slick to seat it)
NEVER trust the fit, ALWAYS carry the slick by the steel neck.
If the space bothers you, try trimming a little at a time of the small end, if the first cut ddoes not allow it to seat deeper then the taper is wrong and should be redone......learning to turn wood is fun.

Bob