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.
#22 Shellholder fits:
Warranty: If any of your RCBS equipment breaks or doesn't work, they will fix it or replace it. No time limit. No questions asked.