There are 2 basic rifle dies that are needed to complete the reloading process. The first is the resizing/depriming die and the second is the bullet seating/crimping die.

Brass must be resized because when a cartridge is fired, the case expands to fit the chamber. The case must be resized to factory specs when reloading to insure reliable functioning. All rifle dies are made of steel. This means that to resize the brass, case lube is required. Case lube will prevent the case from becoming stuck in the die. Sizing dies come in 2 main styles, full length and neck. Both styles of dies will remove the spent primer from the case while resizing the brass.

The full length die does exactly what it says; it resizes the brass back to factory specs from the neck all the way down to the base of the case. This die should be use when loading for semi auto, lever and pump action rifles or when loading the same caliber for multiple guns. Full length resizing insures that the reloaded ammunition will function properly in these types of firearms. Full length sizing can be used for any type of action.

Neck sizing dies resizes only the neck of the brass and should primarily be used when loading for one rifle, usually a bolt action. The belief is that sizing only the neck back to factory specs will enhance the accuracy of the cartridge because it will fit the chamber of a particular rifle better and allow less case expansion during firing. It is also believed that by not working the brass in a full length die every time, case life will be extended. Neck sizing is not recommended for semi autos, lever and pump action rifles due to reliability issues. Neck sizing is also not recommended for multiple firearms in the same caliber unless brass is kept separate for each rifle because chambers vary in dimensions.

The seating/crimping die pushes the new bullet into the case and is adjustable for depth. There are several variations of seating dies but all perform the same function. The seating die can also be adjusted to crimp the cartridge around the bullet. This is sometimes desired in semi auto actions and tube fed firearms so the bullet will not move in the case during recoil.

Most manufacturers will offer variations of these dies. For example, match grade dies will hold the ammunition to tighter tolerances for better accuracy. Other variations are collet dies that squeeze the neck down to specs and body dies that resize the body of the case only.

These resizing and seating dies are most commonly purchased as sets but can also be purchased individually.

Reloading Basics - Getting Started - Click Here
Reloading Presses - Click Here
Reloading - Case Preparation - Click Here
Pistol Dies - Click Here
Rifle Dies - Click Here
Powder Measures and Scales - Click Here
Reloading Quick Reference - Click Here