Lee guarantees in writing There is no loading system that will load more accurate ammunition than Lee Collet Dies, guaranteeing the “Smallest group size or your money back.” A collet squeezes the case neck against a precision mandrel for a perfect fit with minimum run-out. No lube case is needed. Cases last ten times longer, so the savings on only 35 cases will pay for the dies.
These dies size only the neck to preserve the perfect fit of fire forming. Only reload cases that have been fired in your gun. Not recommended for autoloaders, slide or lever action guns.