Why a three die set?

[Alamstutz]

I am wondering why a hand loader would buy a three die set for loading 9mm (or any pistol cartridge). I thought that a final run thru a crimp die was necessary to insure proper chambering of a cartridge. MY UNDERSTANDING is that a three die set (without a crimp die) will not produce a usable cartridge. SO, why so many three die set being sold????

[Dirty Rod]

Not sure I completely understand your statements. Your typical 3 die pistol set comes with a seater die, sizing die, and a crimp die. Some 4 die sets come with an expander die but some presses don't need it. The Dillon progressives, for instance, flare as part of the powder drop using a powder funnel not an expander die. That said, there are some pistol bottleneck cartridges that don't need a flare so you wouldn't need a crimp die. There are also die sets that use a combo seater/crimp die. The RCBS 3 die sets, for example, come with a sizer, expander, and a seat/crimp die.

Edited April 14, 2014 by Dirty Rod

[a.roberts]

Hornady ships a sizer, expander, and seat/crimp in their 3 die sets.

[sk330lc]

Most three die sets from companies like RCBS , Hornady and Redding. Come with a Sizing/decapping die, an Expander die and a combination Seater/Crimp die. The bullet is seated and crimped in one operation. Some find this undesirable and wish to crimp in a fourth stage. Hope that's what you were asking.

[LilBunniFuFu]

Seater/crimp die removes the need for that fourth die.

[Alamstutz]

Exactly what I was wondering. Thanks. I didn't know three die sets also had a crimp function

[polizei1]

Like said, they combine the seating and crimping in the third die. It's better, IMO, to separate them.