Re: Once fired Brass
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Rickp</div><div class="ubbcode-body">Never mind about head space.
Also, now with a formed brass, one can get chamber dimensions from the brass. From there one can just push the shoulders back .001 to .002" and you're done. If I remember right. That's what I wanted to find out here.</div></div>Headspace is critical. That's the dimension that separates safe ammo from dangerous ammo. The .308 headspaces in the chamber on the shoulder of the case at .400 inches. So, headpsace on a .308 is the length of the case from the case head to the first place that the brass case contacts the chamber at .400 inches - the shoulder.
If you want to push the shoulder back you will need a FL or body sizing die and a way to accurately measure how much set-back you are getting.
Depending on the chamber, after a firing or two you will have to bump the shoulder or the case won't go in the chamber any more without force. If you don't body size, and end up forcing your bolt closed on a live round, you will be using the bolt lugs as a press to resize the shoulder of your brass. That's a bad thing.
I sometimes use neck dies for prepping new brass, because unfired brass is undersized and I don't have to worry about shoulder contact with the chamber.
Bottom line: Because we have reliability requirements of our ammo, and we use 'standard' chambers (more or less), we are not using custom chamber dimesions to control the dimensions of the brass like Benchresters do and therefore we have to resize our brass to a greater degree.