Contributed by our own Uncle Don
Proper Die Set Up
Some brands of dies are manufactured differently than others and should be set up slightly different. For Lee and standard RCBS and Hornady dies, the proper headspace is built into the length of the die. Therefore, you should set them by placing the ram in the up position with a shell plate or shell holder installed. Turn the die into the press until you can’t turn it anymore. At this point, lower the ram and turn the die in between a quarter and one half turn.
On standard 7/8 x 14 threaded dies, a quarter turn equates to about .018 of an inch. This is negligible as to the operation of the press but does create an environment that when you raise the ram, you are able to eliminate any daylight between the shell holder and the bottom of the die.
While some people tout an “over-center” feature of a press, it is not necessary or even advised if your die is set properly. About 25lbs of pressure on the handle can equal 600 pounds of force on the press.
I can’t speak to other brands of dies but I am aware of at least one brand that should not be set in the above manner because it would create excessive headspace. With this type of die, proper setting come with trial and error until your case properly seats in your rifle with the action able to close on it without undue effort. This type of die would include specific instructions advising how to arrive at the proper setting.
The flaring die creates a bell in the case mouth of the case allowing the bullet to be seated into the case without shaving lead or copper off of the bullet. These dies are most common with handgun dies as well as rifle dies that are essentially straight walled. The idea is to raise the ram with an empty sized case in the shell holder. Repeat the process gradually turning the seating die down until you get a slightly belled case when your ram is at the top of the stroke. Too much bell is not desirable, as it wears out the brass faster and can reduce the grip of the case on the bullet.
For Lee dies, simply turn the powder through flaring die in until it touches the shell holder and then back it out one half of a turn. If you are using an Auto Disc Powder Measure, no further setting is necessary, simply remove the hex nut at top of the die and turn the measure into the die at this setting. This results in a properly charged case each time as long as you are pulling the lever to the bottom of the press stroke.
Seating & Crimping
This die setting probably causes more headaches for new loaders than any other die. This is because you are asking it to do two things at the same time. Raise an empty case to the top of the stroke, and while holding it there begin turning the die with the lock ring in the upper position and the adjustment screw turned outward into the press until it stops. This is where the crimp shoulder in the die has contacted the case mouth. Set the lock ring at this point and lower the ram to place a bullet on the case.
Turn the center adjustment of the die in slightly and raise the case into the die. This will begin to seat a bullet but won’t crimp it. Lower the case, and turn the center adjustment in a bit more. Repeat the process until the bullet is seated to the depth you want
At this point, lower the ram and loosen the lock ring and turn the die in about a half turn. At the same time, bring the fine adjustment screw outward about two turns. Raise the case (that you just seated the bullet in) into the die. This should crimp it properly. With the ram still raised, turn the center adjustment downward until it stops. This sets the proper bullet seating length.
You now have a “dummy” round and future settings are very easy. Place the “dummy” round in the shell holder and raise the ram. Turn the die with the center adjustment turned outward as well as the lock ring, into the press until it stops. This is the proper crimping setting. Turn the center adjustment down until it stops. This is the proper depth setting.
Lee produces the only factory crimp dies I am familiar with. Factory crimp dies for rifle and handgun are different in that the rifle crimp die uses a collet to apply the crimp while the handgun factory crimp dies utilize a bushing system. The handgun dies also contain a carbide ring like the sizing die which “post” sizes the case to ensure proper dimensions.
To set the rifle style dies, place the case to be crimped in the shell holder and raise the ram. Turn the die in until it stops, lower the ram and turn the die in about a half turn more. This applies a normal crimp and fine adjustments can be made from there.
For the handgun factory crimp dies, turn them in until they touch a raised shell holder without a case present. Ensure that the center adjustment is turned outward. Lower the ram and place a case to be crimped in the shell holder and raise it into the die. There may be some resistance as the case goes through the carbide ring, but it should not be excessive. When at the top of the stroke, turn the center adjustment down until it stops. Lower the ram slightly and turn the adjustment ring about a half turn and raise the ram, the proper crimp is applied at this setting.
Handgun factory crimp dies for straight walled revolver cartridges apply a roll crimp. Factory crimp dies for cartridges that headspace on the case mouth, such as semi-auto cartridges, apply a taper crimp. However, excessively crimping with a taper crimp die will cause it to apply a roll crimp as well. If you are rolling the case mouth into the side of the bullet, you are applying too much crimp for semi-auto cartridges.