Lock ring preference
should be largely dependent on what kind of press you use.
Once adjusted and locked they never seem to move.
I agree, the nut doesn't move, if you aren't inept. But I also agree with Cfullgraf. The nut
can move while screwing the die in/out, even if you turn just the nut. You may have to turn both, together, to ensure it doesn't move.
your press is tighter than mine on that hole then man..
It's not the "tightness" of the hole or the threading. No matter how loose the threading, the threads on the die will be pushing UP against the threads of the press as you torque the ring down. This can make the die stop moving while you turn just the nut. It might happen only with certain dies, at certain points of adjustment, but it certainly can happen on any press.
Of course, this is easily overcome with a little experience and feel, if you take care and pay attention when screwing in the die and nut together. BUT... you can still end up with small variations just due to where you stop torquing your die in the press. Cuz with the Lee rings, you can always manage to turn a bit more or less, depending on how tight you squash the O ring.
I tend to aim my adjustments to where one corner of the lock ring points to a specific mark on my press, so I know where I'm supposed to stop tightening. But this takes more time and attention, on top of making sure that the lock ring doesn't move in relation to the die.
The one benefit of the Lee rings is that they're faster and easier to adjust. No question, there.
So let's look at how people use dies. Over a lifetime, a SS press user might screw a die in/out hundreds of times and adjust it only on rare occasions. So the advantage for SS press users goes to Hornady split rings, IMO. (Or the Breechlock bushings, except they're more expensive.) Yeah, the hex screw locking rings are a relative PITA to adjust, but you don't have to do it very often. OTOH, the hundreds of times you screw the dies in/out, you can zip it in with one hand, turning the die from the top, without looking or paying attention. And when it stops, it's tight. You don't have to carefully torque it down another quarter
-or-so, like with the Lee ring.
But the turret/progressive user that uses tool heads/turrets might screw a die in only once. So I don't see why anyone would object to the Lee ring, in this scenario. They'll stay put if you're not messing with them, AND they're easier to adjust when you WANT them to change.
