A full-length sizing die is designed to resize the entire length of the cartridge case, not just the neck. Unlike neck-sizing dies, which only resize the neck portion, full-length sizing dies are versatile and suitable for any rifle chambered in the same cartridge. When you fire a cartridge, the brass case expands to fit the chamber of your rifle. After firing, the case contracts slightly, but it may not return to its original dimensions. The full-length sizing die restores the case to the correct dimensions by resizing both the neck and body. It also removes any bulges or irregularities caused during firing. Setting up a full-length sizing die involves several steps: Cl Mfg: Lee Precision