Could your rifle need adjustment of the headspace? Wouldn't be the first one.

"Over-sizing brass". I'm going back 20 years or more here - - I remember that some .308 dies were designed to "small-base" the brass to make semi-autos more reliable. Is it possible that the dies you have are doing this? Measure a sized case 3/8 inch up from the base, and compare to a fired case.

Put an empty but primed case in the gun and fire the primer. The real caveman way of checking for excess headspace. The primer will back out by exactly the amount of headspace you have. Pistol primers work better for this trick.

Personally, in a bolt gun I consider .004" shoulder setback to be quite a lot. I try not to set 'em back at all, until the bolt starts closing hard.