The 3-Die Roll Crimp Set is for loading straight-wall cartridges. Its steel Sizer Die sizes the case and de-primes. Note: Cases must be lubricated. 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. Cases must be lubricated Steel Sizer Die sizes the case and de-primes Expander Die expands the case and imparts case mouth flare/bell Seater Die seats and roll crimps the bullet Made in USA