I am using redding's compition bushing neck die in 308. My loaded ammo to start out was .332 so as
the directions that came with the die said I went with a .331 bushing. Now after firing the ammo the
neck expands out to .341 being that this is .009  Is the .331 over working the neck? I was thinking of
trying a .334. I'm wondering if it will allow smoother bullet release and not work the brass so much.
Or am I just getting away of the whole concept of a bushing die? Does redding tell you this to give you
a starting point.? Are the bushings trial and error til you find the size that gives you the best accuracy?

If you go to the .334" bushing your brass won't hold the bullet. As it is right now you are only using approximatelt .001" of neck tension when you take spring back into consideration. This is just fine for a bolt action, don't use them in an auto loader.

How's your brass read for run out? Unless you're getting excessive run out on the loaded rounds I would leave it alone. If however you find that several of the rounds are "wobbly" in the neck you may consider neck sizing in two steps. This has help some get better indicated run out on loaded rounds. Use a .336" on the first pass, then the .331" on the final pass.

I also use the Redding bushing die and for all my .308, LC, Lapua, Win, R-P, Fed, GGG and others I have not yet found any that had a loaded diameter of .332.  My smallest bushing is .333 and I have never yet used it.  If you have turned your brass this could of course thin the necks, but whatever... it is what it is.  



The "fattest brass" I have is the Federal Gold Medal and it has a loaded diameter of .339, my chamber opens this up to .3455, so I size first with a .340 bushing, and then a second pass with a .336 or a .337.  What I am saying and I think you are asking is can I size .009 in one pass... I think it is best not to.



Those are my 2 cents.

My run out is averaging .003  I felt like that was pretty good. I have considered turning the necks to maybe get it even better, but shooting a factory chamber at this point and didn't think it would make enough diff compared to how much I'd be working the brass.
I am in the process of building a 6.5-284. witch it will most likely be a tight neck chamber and neck turning will have to take place, but that is another thread. lol anyways I'm working on getting my 308 to shoot the best that it possibly will, or yet I'm trying to just do
the best I can on my part. so the rifle will do the best that it can.
Thanks for the info.

The brass that I'm using is win. , but the brass has been shot 3 times before the bushing die was purchase and starting using. I didn't messure factory ammo. there never has been any factory ammo shot in this 308. maybe with the brass being shot
3 times thined the walls out and how I got .332 to start?

Measure your case neck wall thickness multiply it by 2 and then add the caliber.  Then take 2 or 3 thousandths off to arrive at the bushing size.  

It would not make a differnce if you started using the bushings later in the case life, either.  Except that for the resizings prior to the bushing sizer you were lengthening the cases by dragging them over the expander.

As alluded to above  I make two passes in sizing my Lapua brass.....I size 339 first then 336 second, and with the WW brass 336 first then 331.