I have never owned a progressive press but it is my understanding that Dillon dies are all small base dies.
My point being that the majority of precision ammunition I read about is made on a single stage press.
And I'm still using the Rockchucker press I bought in 1973 and prefer that the die makes hard contact with the shell holder with press cam over.
I think of progressive presses with making bulk pistol ammunition and blasting ammo for semi-autos.
To me going slow on a single stage press ensures quality and uniformity with more time to double check everything.
I'm retired with nothing to do and all day to do it and reloading to me means making better ammunition than factory and going slow.
And the best dies are Forster full length benchrest dies with their high mounted floating expander for making very concentric cases with little to no neck runout.
My second choice for cost and performance would be Lee full length dies with their fixed ridged expander. This die has less chance of locking the expander off center and inducing neck runout. And with any die it helps to have a run out gauge when setting up you dies and checking for minimum neck run out. Just remember you will also see any case neck thickness variations when measuring "neck" runout after sizing.
This is where having a simple Redding neck thickness gauge helps, and with one turn of your wrist you will see the total neck thickness variations. When using this gauge and have a .003 neck thickness variation your neck runout should be as close to this reading as possible when setting up your sizing dies. Meaning the expander is not pulling the case necks off center.
