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:
.30 Luger (7.65 Luger)
.30 Mauser (7.63 Mauser)
.356 TSW
9mm TSW
9mm FAR
9mm Luger
9mm Makarov
9mm x 21
9mm x 23 Winchester