Dan in MI wrote:
The question of crimp or no crimp is easy. Crimp
That's my vote, too, based on observation of factory ammo. They know a whole heckuva lot more about making ammo than I ever possibly could, and all the factory stuff I've examined was crimped. Different styles of crimp, depending on whether its for an auto or revolver in handguns, or what the intended purpose of rifle ammo is, but all crimped.
So it looks like the only question is HOW to do it. As Dan says, there's a lot of Ginger or Mary Ann involved, and one of the beauties of handloading is there are usually several ways to approach, and solve, a given problem.
For myself, I prefer seating in one operation, crimping w/ a separate die in another (I use Lee FCDs on my ammo.) My results and testing support the idea I can do a better job w/ less work that way than when I used to dink around w/ the seating/crimping die to do both jobs and having to get it just right w/ different bullets, cases and such. Call me lazy, but any time I can get the same (or better?) result for less effort, it seems a good thing.
But YMMV, and I'm not here to say any other way is better/worse than mine! That's another beauty of handloading: you get to play, test, and find out what YOU like best!