You only have to worry about headspace once, then the brass is fireformed to the chamber, and will stay that way unless you set the headspace back when sizing the case. No problem.
My father had a beautiful Kimber 22-250 that had a dangerously long chamber. His cases lasted 2 firings, because he didn't understand that you either create a false shoulder, or jam a fireformer into the lands for the first firing, then your brass is GTG for the duration, when sized properly. My brother inherited that Kimber. The headspace is at least .05" too long, but the firing pin must compensate a bit, because it doesn't misfire as often as you'd think it should with new brass and jammed bullets. Sure, one could expect Kimber to build a high-dollar gun right the first time, or to make it right, but....well, I wouldn't count on it, and neither did my brother. Easy fixes.
