The action will not close with a .004" piece of paper on the NEW empty case base. It will not close enough to trip the locking lever, so headspace is tight. Left barrel still printing about 3" to left of rt barrel, but the good news is it prints a tight group(1 1/2" at 50 yds with express sight, and 68 yr old eyeballs). I'm sticking to the no-stretch limit for max loads. My 350 gr load is 75 gr of 4064, and a win mag primer.