I shot the Bruno 00 BT for a long time with a .050" freebore. Worked great. In the .015" freebore, I can jam it as much as I want. But the bullet base is not near as far down the neck as it is when I seat a .825" FB bullet to a similar jam.
Ogive location is more key than jacket length in determining what the freebore should be. Consideration must also be given to where the bottom of the bullet will be in relation to the neck and powder.