Measuring Headspace on New AR

Chipster697

Private
Minuteman
Sep 6, 2010
13
26
Sorta Downeast
Can I use once-fired brass as a good indicator of headspace in a new AR-15?

I know that in an M14/M1A the brass is still expanding during extraction so spent cases are a no go unless you turn the gas system off and manually cycle the rifle.

I've got Hornady's headspace gauge for measuring purposes.

Barrel is from White Oak Armament with a Wylde chamber, and WOA headspaced the bolt for me.

Sorry for the basic question. Hopefully your answers will help others as well.