It seems like brass these days has more concentric necks, and this doesn't seem to be as
needed as it was years ago. I think the brass manufacturers have fianlly figured out that
1) concentricity is important and 2) how to actually control it in their manufacturing process.
I have a Forster, and have used it, but most brass today is pretty darned consistent, plus
discussion with a friend who was a national champion benchrest shooter, and who made
his living making benchrest bullets for a decade let me know that this is usually not much
of a problem with normal chambers in normal guns. In benchrest guns with super tight
chambers, esp the necks, it can be important to thin the neck to get just enough clearance
to release, but still align the neck (bullet) very precisely with the bore.
Try it , esp if you have a bunch of old brass and a really accurate rifle. Never hurts, and it is
fun to learn.
If I ever turned 500, I could see getting a power rig. Usually 50 at a time or so, and so far, no problems. I have thought about powering up the trimmer, but it just hasn't
yet been enough of an issue to bother.
I use the shell holder for the Lee case trim set when I neck turn, using a battery drill. Mount case - length trim with Lee trimmer- deburr- neck turn. I haven’t really found a clear accuracy advantage in my rifles, but at least it is reasonably quick this way.