Really, I would have never figured that out, it cases excessive neck expansion and can make the cases hang or bind, even more so if they aren't evenly and smoothly turned, and if turned to much they will split and hang up. Btw I just started doing this yesterday!
In a bolt action rifle, if the rounds chamber easily and the chamber is clean but bolt lift/ejection after firing is hard, the pressure is too high irrespective of what the load is or what the primers look like.
I've seen instances where a normal load in a round fired in a chamber where the bolt face is way out of square, the case head gets out of square and the bolt binds when it's opened. When the high point of the case head aligns with the high point of the bolt face (opposite from the low point at the fired case head's high point when fired), there's not enough clearance; the bolt binds. Especially if the case walls are uneven in thickness to cause more stretching on their thin side that just happens to be aligned with the bolt face's low point in its out of square condition.
My 700 5R was having the same problem, stiff bolt lift and hard extraction. A thorough chamber cleaning and polishing eliminated the problem completely. Remington 40X bore cleaner on a cut down shotgun mop chucked in a drill and turned very slowly did the trick.
You are right about that Bart. I thought I was cleaning but it just wasn't good enough. I realized there was a small almost scratch like area just ahead of the belt on each case so that's why I polished it. If there was a burr in there the 40X got it out but I still clean the chamber thoroughly with a brush each time.