New Alpha 6GT brass, excessive headspace?

[Jake the dog]

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.

 

[Steel head]

If it truly has to stretch ten thou plus on initial firing that’s not very nice on the brass.
You can mitigate that by hard jamming the bullet or a false shoulder on the first firing.

 

[Supersubes]

It’s your measuring tools. Wait till you get the barrel and fire some of them. Then you can take a “comparative” measurement. Your headspace tool is a comparative tool, not a gauge.