If your shell holder doesn't securely grip the sell and firmly fit into the press during reloading, you're bound to have headspace and sizing problems. RCBS manufactures their shell holders to the industry's tightest tolerances, using only the finest steel.
Fits:
.45 Colt
.454 Casull
WARNING:
Handling firearms or firearms parts can expose you to lead and other petroleum products known to the State of California to cause cancer, birth defects, or other reproductive harm. Wash hands thoroughly after handling. For more information go to www.p65warnings.ca.gov (CA Health and Safety Code Section 25249.6).