Hoot, the chamfering tool is mainly to remove burrs and rough spots left from the cutter when cases are trimmed. If your cases have a smooth, angled shape just at the mouth then it is most likely working. I have never worked with a .17 before but have found with smaller calibers when not using a boat tail bullet I can not easily get the lighter bullets to set on top of the case, remember the case neck is sized down just a few thousands smaller than the bullet in order for the cartrige to grip the bullet when it is seated. Try using your fingers to hold the bullet over the mouth until it starts into the die and feel for the bullet to strart seating, if it takes exsesive force and kinda pops into the case then it could be the chamfering tool. Hope this helps.