I have a Forster competition die set for my 7x57mm. The full length resizing die has an expander ball that can be screwed up the decapping arm so it does not contact the cartridge case. Is there an advantage to not using the expander ball when sizing cases on every resizing. Should you screw the ball back down so the expander ball contacts the case ever second or third resizing. Any help would be appreciated folks. Tom Purdom

I own a few sets of forester and I'm not sure if my sizing die is the same as yours but the whole idea of the forester die is that you keep the ball up into the die further than other dies. Thus you still have a grip on the case when it goes over the ball with the sides of the die and that should help concentricity. Also being the ball is located closer to where it is anchored (near the top of the die) it should be better centered in the die. Now as far as screwing the ball up away from the case I would think you cannot have it so far up into the die that it would be adjacent to where the neck is sized. I guess I'm not aware of how you could have it so high in the die that the case didn't touch it during normal resizing.

When I got my foresters I did a little fiddling till I got the sizing stem perfectly seated in the middle of the die and they make great runnout. I rarely get over .002" loaded ammo for my 300 wby. For me once you get die tuned right trying to size without the ball is just going to add more useless steps.

I have good results with Forster, also. Their instructions say that if you screw the expander ball too far up you can cause damage. The bottom third of the expander ball should be even with the vent hole in the die or damage will ensue.

One of the benefits of Forster is the somewhat loose decapper/expander ball rod with an o-ring. This looseness allows the expander ball to "float" a little, so as to find the center of the case neck, rather than to insist that the center be where the rod is. This kind of duplicates the Barsness approach, since he prescribes a very loose fit ("one or two threads") of the rod in the die before driving it into the case neck.

Jaywalker

Thank you all: As usual my question has been answered. Respectfully, Tom Purdom

Tom--I'm going to past below how I tune my dies. It's worked really well for me and others and I hope it can for you too.

My $.02 worth---ALL dies with expander balls need tuning. Think about it...a piece of typing paper is .003" thick--what are the odds that the expander is not PERFECTLY centered in a die??? Pretty good I'd say. Pull the expander stem out of the die (and now is a good time to clean the inside of the die). Run about 5 brass into the die and see if they come out concentric. If they do (and usually they will) you now have to try and get that stem centered on re-assembly. A great way that helps is to put a piece of very concentric brass up into the die to hold the stem in place as you tighten it down. Sometimes this takes 2 people unless you have 3 or 4 hands. AFter reassembly try sizing some brass and check runnout. If not good then do very small turns of the expander stem--probably 1/32 of a turn at a time. Resize some brass and repeat the small turns. At some point I can almost guarantee that you will get GREAT RUNNOUT CONSISTANTLY. (Somehow, someway the expander spindle will hit almost perfect centering in the die body) I have many dies that consistantly make less than .002" runnout after sizing with most of the brass at .001" and less. I own, hornady, redding, forester, rcbs, and lee dies. ALL OF THEM HAVE BEEN TUNED and most make fantastic ammo and all make good ammo!! I have never ever got a set of dies from any factory that made as good of ammo as those that I have done this simple work with.