I have a Lee factory crimp die for 45/70 to allow me to crimp that big bullet separately. The instructions say to crimp any bullet, and it will make it's own cannelure. They probably singled out Speer, because Speer has held for 20 years that I know of not to crimp any of their bullets that do not have a cannelure for that purpose.
There are three kinds of men:
1) The ones that learn by reading.
2) The few who learn by observation.
3) The rest of them have to pee on the electric fence and find out for themselves..........