Different Types of Reloading Dies

Reloading dies deprime, resize and expand cases and seat and crimp bullets. They can be made of steel or carbide. Carbide dies are more expensive, but last longer and require less lubrication than steel dies. 

Lee Precision offers several die sets, including their American Series that is very basic at a low price and comes in popular cartridges with a shell holder included. It features a split lock ring with wrench flats and a knurled body. 

Neck Sizing Die 

For reloaders using bottleneck calibers, a neck sizing die works only on the neck section of the case. This helps the case retain its fire-formed “glove fit” into your rifle chamber. This reduces the overall pressure of a cartridge and increases accuracy and case life. 

Carbide neck sizing dies are available from some manufacturers (Hornady, Lee Precision, Lyman) and do not require case lube but do need to be cranked down fairly tight to avoid cases getting stuck in the die. Carbide is also much more expensive. 

A benchrest bushing bump sizing die is another popular type of neck sizer and improves bullet seating by reducing excessive neck tension. These are often used by competitive shooters and long-range varmint hunters. 

Full-Length Sizing Die 

Full-length sizing dies size the case body and shoulder (though some setups also bump the shoulder). They reduce the case diameter no more than a couple thousandths; any more and the case will stretch too much after firing and cause accuracy problems. 

Full length sizing dies also decach cases, which is a great advantage for high volume reloaders, as they can remove the old primer from the case without removing the bullet. This saves time and effort, and helps ensure that the new primer will be seated in the case neck correctly before seating. 

Many reloaders will set up their full length sizing dies to only resize the neck and push the shoulder back a few thousandths, leaving the body of the case unsized (sometimes called partial neck resizing). This is a bad idea; it will not work for most rifle calibers and will usually result in inconsistent cases. When setting up a conventional full-length sizing die, you should use a headspace gauge calibrated to YOUR rifle chamber. 

Small Base Sizing Die 

Typically cartridge specific, they bump the case neck (a small notch at the base) slightly and preserve the fire-formed custom fit that you got by shooting the brass in your firearm. They also resize the case to a smaller diameter down near the mouth. 

This type of die is used for bottlenecked cartridges that headspace on the shoulder,

rim, or belt. It sizes the case from the shoulder to the head a couple thousandths less than the Full Length Sizer Die or Neck Die. 

This is a good set of dies for the beginner because they're relatively inexpensive, easy to setup and use, and include a shell holder. The first die resizes and deprimes the cases; the second expands the case and seats the bullet; the third crimps the case over the bullet. Many of these sets feature a carbide resizing die that eliminates the need for case lube and requires less attention when setting up the presses. 

Seating Die 

For the handloader that wants to take their load quality up a notch, a seater die will allow for a more precise bullet seating process. Many have a micrometer seating stem that will allow for repeatable bullet seating depths, eliminating much of the variations in case/bullet runout that occur in loaded rounds. 

Some seater dies also crimp the mouth of the case, which can be beneficial for magnum cartridges that may experience excessive bullet movement during recoil and cycle of the firearm. Crimping also helps to equalize the pressure of each case, which can help to prevent cases from blowing up during firing. 

Whether bottleneck or straight, all reloading dies perform the same basic functions: they deprime and resize cases, expand them to easily accept a new bullet and seat and crimp it in place. Choosing the right set of reloading dies for your calibers is an important first step to creating high-quality ammunition. Fortunately, you should be able to find a company that can  produce excellent reloading supplies and sets for both rifle and pistol calibers.