The reamer print on the GAP web site shows a headspace dimension of .375 at 1.360-1.365 from the bolt face. My new Alpha is measuring 1.349 to 1.351. I dont have the barrel yet, so I don't know what it measures, but this seems excessive. I usually try to bump .002 for my fired brass. I'm sure the brass will eventually fire form, but the last thing I want is a beat up bolt face and ignition failures.