With anywhere from 1200 to 4500 pounds of pressure pushing against that gauge's threads, there's no need to force it to a dead stop. Wrap some teflon tape around the threads and you should be able to screw it to a stop, then rotate it back to the 12 O'clock position and not lose air, or even get a slight wiggle out of the gauge! At least that has been my experience. You are usually backing it off about 1/2 of one turn of the threads. Glem's mention of an o-ring is also a good add-on with the teflon tape.
Use this technique at your own risk, I did.
Regards,
Kindly 'Ol Uncle Hoot