Now I'm really confused.

I checked the headspace on this rifle with a Forster field gauge. The extractor was installed and I slipped the gauge under the extractor and the bolt completely closed.

I have some Remington 03A3 bolt bodies. I checked the headspace with these bolt bodies (no extractor installed). I slipped the gauge into the chamber and the bolt bodies won't come close to closing on the field gauge.

One other thing--I notice that the third lug, the so-called "safety lug", on the original bolt on this rifle is tight against the action with the bolt closed. With the Remington bolt bodies, the safety lugs are forward of the action, with a noticeable gap between the "safety lug" and the action when they are closed.

Am I unclear on the concept here?

Was my original method of using the field gauge (leaving the extractor installed and slipping the gauge under the extractor) flawed?

Is my method of checking the headspace with the bolt bodies (chambering the gauge and attempting to close the bolt bodies) valid?

Does the difference between where the safety lug fits between the action on the bolt bodies (gap) and the original bolt (no gap) mean anything?

Thanks, Steve