I have read that many people are getting less than perfect necks from the Redding button dies. Seems the buttons aren't always held rigidly so maybe they slide just a bit to one side or other under the forces of sizing. ??? I don't know, but it sounds plausible.
Most bullet misalignment rises from bent necks and most of that comes from poorly aligned expanders with conventional size dies. I've used Kirby's methods for years, ever since I got my first set of Forster BR dies in which the expander ball can be adjusted to anywhere we need it to be. Kirby is right in that many other dies can also be adjusted to do the same thing. If you do it that way get yourself a universal decapping die and use it instead of the FL die's decapper. But, there is another way to expand that I like even better.
Getting seating started square is a real problem area, especially so with flat based bullets. For my FL sizing, I have removed most of my expanders and use a Lyman "M" expander, mostly intended for cast bullets, instead. First, it pushes IN rather than pulling OUT on the sized necks and that leaves the necks measureably straighter. Importantly, it also expands the mouth of cases just a slight bit over bullet diameter which allows me to actually set the bullet IN the mouth, not just balanced on top and hoping it will enter correctly. I love the M dies!
IF you wish to neck size only, the only way to fly is Lee's Collet Neck Sizer die, IMHO. As it comes, it works the brass minimually, won't deflect the neck at all and needs no lube. I have lathe modified my Lee neck sizing collets by cutting a short taper into the split-fingered mouth section, about .030" deep and about a 35 degree angle. Thus modified, they will leave a slight "M" type flair on the case mouth for easy bullet entry. I think it would be easy to grind the same kind of taper with a Dremel tool and grinding point.
While it is certainly possible that some bullet meplats could bottom in a conventional seater stem, and that could be easily corrected by drilling the cup deeper, there is another problem with most of them. They usually are a sloppy fit in the dies bullet chamber so there is little support for centering the undersized stem until the bullet is significantly off line. In my experiments, using a concentricty gage, the "seat part way and turn to complete" does little because the stem is largely unsupported in the critical area of the die. The only cure for this poor fit is to lathe turn a new stem that snuggly fits the die. OR, you can use the full-chamber seaters made by Forster and Redding, which you are already doing. Given that excellant seater, I think your problem is with bent case necks and no press or other seater can fix that.
Last edited by boomtube; 04-04-2008 at 09:00 AM.