Re: Bumped shoulder back too far
The most likely causes are
(a) mixed up load data
(b) scale not calibrated
(c) cases need trimming
(d) bullet seating depth changed from jump to jam
Otherwise, I'd want to know if I had a headspace issue before messing around.
There are a couple of ways to check and cross-check.
A very crude check would be to remove the firing pin and apply layers of tape to the case head to see how many layers it takes before you begin to feel the bolt crushing the tape as it closes. This is by no means precision testing because it requires more feel than something solid and tape isn't all created with equal thickness. So, you would need a mic or caliper to measure the tape thickness to get an idea.
Secondly, you can get a set of Hornady Lock and Load Headspace inserts for your calipers and measure the case length from the datum line to see if the cases are within SAAMI specs. If so, and IF your chamber is also within specs, then you should be good to go.
Thirdly, use HNL headspace gauge to measure some of the loaded/unfired cases to the just fired cases and see how much they've grown.
Headspace gauges will tell you if the chamber's in spec.
I would be inclined to use several methods and cross-check and if there's any doubt, take it to a gunsmith.
Hopefully, it's something simple.