Does Form Firing Matter If Using a FL Die?

[MogollonMan]

I recently picked up some once fired brass from a friend that was fired out of his brother's 300 Win Mag. I only use FL dies when I reload. My question is does using the FL die completely return the brass to the original shape, or does it still retain some form features from the original firing? Will there be a difference if I reload, shoot it through my rifle (reform fire) and then run it through the FL die again? I hope that makes sense.

 

[lancetkenyon]

You will need to set up your die to bump the shoulder back for your chamber. Just because chambers are cut to SAAMI specs, doesn't mean they are all cut the same. You can FL resize your brass to your chamber specs (shoulder bump back), and they might differ to someone else's chamber.

 

I would just FL size them with the shoulder bump back you need, and don't worry about them being shot in someone else's gun first. They chamber easier when you FL size them anyway, which is important in a hunting rig.