I'm surprised no one has mentioned this, considering I've said it plenty of times over the years but you need to seat the bullet so that the driving band groove is almost buried beneath the mouth with a little still peeking out, then drive the taper crimp down into the groove. Holds on quite well and without crimping down below about .474. I've even posted images and drawings about this. Also works on bullets with cannelures.
Hoot
Google is a great search engine when you point it specifically at this site as covered in this thread in the Hoot's Information Depository sub-forum.