In this video, Bob Dunlap and Ken Brooks from the American Gunsmithing Institute (AGI) take a Mauser rifle, and shoot some 8mm Mauser military ammo, as they adjust the chamber from 0" over the no-go length, to 0.045" over the no-go length (that's 0.051" total headspace).
I thought it was interesting. Video is almost 25 minutes. Video quality is not real good though.
If you've never seen case head separation, you'll see some examples of what it looks like.