Federal has been known to use softer brass, one of the reasons Fed GMM brass doesn't last as long as Lapua or Winchester brass, but also one of the reasons why it is so consistently accurate.
As long as you are loading a middle of the road 223 pressure spec load I think you should be fine with FC marked brass. I wouldn't go for a full house 5.56 pressure load.
Jimro
__________________
Machine guns are awesome until you have to carry one.
|