IMI barrel headspacing help

I bought a new, undrilled IMI barrel and I'm ready to heasdspace it. When I screw it into my ORF receiver and do a test fit, it closes on a no-go guage. That means I have to remove some material from the barrel shoulder until it will not close on the no-go guage right? Now, is the barrel "shoulder" the ledge in front of the barrel threads that contacts the receiver, or the face of the barrel that makes contact with the bolt. Thanks in advance!

Shoulder is the area where the barrel contacts the forward front of the receiver. Does your bolt close on a field gauge as well?

How much torque did you put on the barrel before checking headspace? Don't use final torque specs when first checking but get the torque up near there to check headspace.