Powder loads 300 win mag

[SSG Graybush]

Now that's entirely the opposite of what others here are saying. Without first fire forming there is no way you will be able to bump the shoulder back .002". If you take a fired case from your rifle and FL size it you're defeating the purpose of fire forming.
You do run the case into the FL sizer but only enough to bump the shoulder back AFTER fire forming to your chamber. Once fire formed and shoulder us bumped back, work hardening of the brass is minimized. You will still be head spaced off the belt but your case shoulder will be closer to the chamber wall.
I believe we may be stating the same thing and NOT fully sizing the brass by camming it fully into the die.

With virgin brass you could neck size only or you could lower you FL die down to the point to where it's touching or close without bumping the shoulder. That will size the case enough and round out the mouths. Fire and then start bumping 2 thou from the longest case(at datum line) and then maybe 1 thou more if it's too tight on bolt closure, the next sizing. Am not saying bump new brass 2 thou back when it's probably 4+ thou back already.

 

[southpa]

My thoughts are that if he is asking the question, what reason is there that we don't help him? It is a reasonable request, why not help?? I've been reloading for more years than I care to say, but…when I read the caption I clicked on it looking for any information that could be taken from the thread. My son has a 300 WinMag that I'm still working on load data for, that is my reason for viewing this thread. Who knows he may take something back to his friend that would help his friend to develop better load data than his friend already has.

Ya and couple that with the fact that the OP literally said "i just hate to keep asking him" seems pretty obvious why he's asking for help...Some people just cant help but go out of their way to to be arrogant....
Stick around @sooner2000nc there will be a wealth of knowlede to gain from members who actually care to help. Lots of good info already.

 

[carpassasin]

I agree weed through and gleam what knowledge you can! Remember it's fun enjoy.