The 3-Die Roll Crimp Set is for loading straight-wall cartridges.
Its steel Sizer Die sizes the case and de-primes.
The Expander Die expands the case to the proper diameter to accept the bullet, and it imparts case mouth flare/bell for bullet feeding.
The Seater Die seats the bullet and roll crimps.
Note: Cases must be lubricated , Shellholder sold separately.