While the bullet seating die that comes with the die set will apply a crimp to the case, there are some great advantages to using the Factory crimp die. One is that cases are post-sized by the carbide sizing ring in the base of the die. This is like the sizing ring in a resizing die, except that it is ground to maximum allowable outside diameter for the case involved. So if there is a buckle in the case from excessive crimp or a bulge from a slightly oversize bullet, the complete cartridge is resized as it is withdrawn from the die; You can be certain that it will chamber, because it has been resized after the bullet was seated and crimped. There is no provision for seating the bullet with the Factory Crimp Die.
The type of crimp on the die depends upon the type of cartridge. With cases that headspace on the case mouth such as the 40 S&W, 9mm Luger and 45 ACP, the die applies a taper crimp (compresses a longer section of the case mouth into the bullet). On other cases, like the 45 Colt, a roll crimp is applied (rolls the end of the case into the bullet).
The degree of crimp is adjusted by how far down the knob on the top of the die is turned in. The proper setting for this die is with the adjustment knob turned all the way up, turn the die into the press until it touches the shell plate or shell holder which should be in the raised position. Then, raise an empty case into the die and begin to turn the knob inward until you feel it stop on the top of the case. Another 1/2 turn will apply a good crimp and you can adjust from there to suit your specific need.
