Lee turret press

[Lindsey]

Lee just introduced a new 4 die turret press. There are some great deals available on the old model, 3 die turret press. The 4th die position is for a crimp die.

Is the crimp die something that I really am likely to need for reloading for revolvers and box magazine rifles?

The price difference between the 3 position press and the 4 position press is about $35., or the cost of a good set of dies.

[Mr. 16 gauge]

Lindsey;
For the revolver loads, I would say no, you don't need the extra crimping die. In my dies (and I have LEE pistol dies), the bullet is crimped in place after it is seated in the case--the bullet seating die does both jobs.
As for rifles, the answer is "maybe". Are you shooting a autoloader or pump, and if you are shooting an autoloader, is it a military-style autoloader? These usually (but not always) require that the bullet have some crimp on it, as the slam-bang of the action will tend to push the bullet in the case. If you are shooting a rifle with tubular magazine, such as a .30/30 or .44 magnum lever action, then the bullets need to be crimped in place.
But I believe if you use bullets with a crimping groove, you won't need a crimp die for that, either, as you can crimp the bullets into place with the bullet seating die (I do this with my .30/30 loads).
I beleive that the extra spot in the turret is for a "taper crimp" die, one which will put a crimp on the bullet by thinly tapering the case so it holds the bullet firmly. This is done on bullets with no cannelure, as not to damage them and decrease accuracy.
Once the bullet is seated, you can always remove the bullet seating die, put the taper crimp die in, and run your loads through again....might take a little more time, but it should work just as well. Good luck.