The RCBS Small Base Sizer Die Set for .223 Remington/5.56mm is specifically designed to ensure proper functioning in semi-automatic, pump-action, and lever-action rifles. This die sizes brass to minimum specifications, creating a smaller diameter and setting the shoulder back slightly more than standard full-length dies. Equipped with an expander-decapping unit, it removes spent primers while prepping cases for reloading. Not recommended for bolt-action rifles, this die provides reliable and consistent performance for reloading semi-automatic firearm ammunition. Shellholders are sold separately, and a storage box is included for convenience.