Stix wrote:I wonder if its worthwhile to buy snother mandrel & cut the pin orf of one...or get a uni decapping die...
wobble die is a die that uses a expander ball to open the neck back up...
They're rarely concentric for some reason--if you loosen the lock ring, turn it upside down & turn the mandrel/stem, youll see the expander ball doing circles.
If you lock it off, you'll often see them not centered...
You are probably better off getting another mandrel and cutting the decapping pin off. At least you don't have to pull the whole die apart to do so, just take the top cap off and swap pins. You can probably do that without even taking the die out of the press.
"wobble die"... Okay, but some dies don't do that, The decapping stem and expander are pretty much in the center. Some dies don't have a button but a longer tapered expander and a thicker stem. Now, which ones they are I can't remember but a quick look in the cupboard and without pulling dies apart, RCBS have a small button but Redding, Forster and Hornady don't. As best I can tell with a torch.
I have seen what you describe with my RCBS Dies and from memory I pulled the whole stem out, took off everything and rolled the stem over a flat surface to make sure it wasn't bent in any way, if so fixed the out of round. Also from memory I moved the whole stem around whilst the locking nut was just loose enough to rotate the stem then found the best center before locking the stem.
Actually, there would be enough length in that sizing stem to move when you are pulling it back up the neck to size and I doubt very much that it would actually pull the neck off center especially if the button is lubricated properly. Don't know if you have one but if you have a concentricity gauge you can check case necks yourself with and without the expander ball installed. Check case neck runout and also case runout just past the shoulder on the main body.
Now you know why many use Bushing Dies and those that have an expander they remove it. Also why the Lee Collet Die is the next best to a Bushing Die as both produce good case concentricity.
Okay, been into the reloading locker. I only have one RCBS Die Set and that is the only one with the loose (off center) decaping stem. The Redding Sets are completely different and stronger in their design. I checked a half dozen sets and in each there are two with decapping stems (Full & Neck Dies) all of which are pretty much dead in center and don't change when rotating the main stem.