A couple years ago we had a brand new fiberglass entry door system
installed - along with a Weiser latchset and deadbolt with a disk lock
- one of those you can rekey any time without pulling the cyl. My
daughter pulled the key out when it was not in the "remove key"
position and the lock would not work or reset. Found that you do NOT
want a key that is basically wedge shaped - you want the end to have
bigger "teeth" than the base.

Anyway, after we replaced it with a new one, it has worked well - but
it has always been a bit "notchy" - sometimes difficult to get the
bolt to extend.
I took it apart yesterdsay, and when out of the door, everything
worked smoothly. Ends up there is a little "toggle" on the bolt
assembly that was hitting the wood in the door - I grabbed a bg round
file and opened up some space above so the toggle didn't hit any
more, and now it is smooth as silk.

Just thought I'd pass it on in case someone else has the same problem.