Reloading ammunition requires a deep understanding of tools called 'dies.' Each of the reloading dies performs a unique function in the reloading process, and knowing how to use them in the right order is critical for safe and efficient reloading. This guide explores different reloading dies, their functions, how to setup reloading dies, and their adjustments. We'll also delve into combined dies, standard die measurements, discuss the necessity of separate crimp dies, and introduce quick-change systems like Hornady's Lock-N-Load and Lee's Breech Lock system.
Key Reloading Dies and Their Functions
Reloading dies often come in sets of 2, 3, or 4, depending on whether some functions are combined into a single die. They can also be purchased individually. Some individual dies can provide utility across different calibers. Many companies make reloading dies, including Lee Precision, RCBS, Hornady, Lyman, Dillon, and others.
Decapping and Resizing Die
Function: Decaps or removes the spent primer and resizes the fired case to its original or specified dimensions. Some people choose to use dedicated decap dies and do sizing as a separate operation. There are some good reasons to do so. Read more about that in our article on decap dies.
Mechanism: The die comprises an internal decapping pin that knocks out the spent primer, and the walls of the die resize the case back to its original dimensions.
Setup and Adjustment: To set up this die, raise the press ram to its highest position, screw in the die until it makes firm contact with the shell holder. Ensure the decapping pin protrudes far enough to knock out the spent primer without damaging the primer pocket.
In a single-stage press, this die is typically used first. For a turret or progressive press, it is placed in the first position.
Expanding (or Belling) Die
Function: This die flares the case mouth slightly, making it easier to seat the bullet.
Mechanism: It uses a belling or expander plug that widens the case mouth when forced into the case.
Setup and Adjustment: With the press ram elevated, screw in the die until it just contacts the shell holder. After lowering the ram, adjust the die a further quarter turn for the right amount of flare.
In a single-stage press, this die is typically used second, following the decapping/resizing die. For a turret or progressive press, it is placed in the second position.
Seating and Crimping Die
Function: This die pushes the new bullet into the case to a precise depth and may also apply a crimp to secure the bullet.
Mechanism: The die features an internal seating plug that pushes the bullet into the case to a predetermined depth. Some seating dies also include a crimping feature.
Setup and Adjustment: Start with the die backed out a few turns. Place a charged case in the shell holder, run it up into the die, and screw the die down until it contacts the case mouth. Adjust the seating plug to achieve the desired bullet seating depth.
In a single-stage press, this die is typically used third, following the expanding die, while it is placed in the third position on a turret or progressive press.
Separate Crimp Die
Function: This die applies a final crimp that secures the bullet in the case. This can be either a roll crimp, which folds the case mouth into a groove (cannelure) on the bullet, or a taper crimp, which applies a slight taper to the case mouth, pressing it against the bullet without folding the brass.
Setup and Adjustment: Screw the die into the press until it just contacts the raised shell holder. Adjust further depending on the type of crimp desired.
This die is used last in a single-stage press, following the seating die
, or placed in the fourth position on a turret or progressive press.
Specialized Reloading Dies
Powder-Filling Dies, Powder-Through Dies, and Bullet Feeding Dies
These dies are utilized in progressive reloading presses to automate some reloading steps. These specialized reloading dies may be used in turret presses to speed up production.
Powder-filling dies meter and drop a precise charge of powder into the case. Powder-through dies allow the reloader to charge the case with powder while expanding the case mouth simultaneously. Bullet feeding dies automatically place a bullet on each case, which can significantly increase the reloading speed.
Stand-alone Decap Dies
These types of reloading dies are used solely for removing the spent primer from the fired case. They're often more durable than the decapping pins found in resizing dies, making them an excellent choice when dealing with military brass with crimped primers or dirty, gritty cases that could damage a regular decapping pin. Even the dedicated decap dies can (and often will) be broken. Decap pins are replaceable in most types of dies including resizing dies, and stand-alone decap dies.
Specialty Warning Dies
These types of reloading dies provide a safety check to ensure the correct amount of powder has been dropped into the case. They include:
- Hornady Powder Cop: Inserts into a station on your progressive press and uses a white o-ring to visually verify the powder level.
- RCBS Powder Check: An audible alarm sounds if the powder charge is too high or too low.
- DAA Magnetic Powder Check: Uses a magnetic sensor to trigger an audible alarm when the powder charge is outside the acceptable range.
Trimming Dies, Primer Pocket Swaging Dies, Bullet Sizing Dies, and Bullet Swaging Dies
These specialized reloading dies perform more specific tasks:
- Trimming dies are used to cut the case back to its proper length.
- Primer pocket swaging dies are used to remove the crimp from military brass, allowing you to easily insert a new primer.
- Bullet sizing dies are used to ensure the bullet diameter matches the specifications for your firearm.
- Bullet swaging dies are used to shape the bullet to its final form and can be used to make custom bullets from lead wire or cast lead cores.
Understanding and correctly using each of these dies is crucial to produce safe, reliable, and accurate ammunition. By following the manufacturer's instructions and taking necessary safety precautions, you can enjoy the art of reloading ammunition.
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