Did you also use a no-go gauge? If not, you really should try one. I wouldn't be surprised if you can close the bolt on a no-go gauge. Did you check the headspace with the go gauge after tightening the barrel nut? I like to feel a little binding or friction when closing the bolt on a go guage.

That is a tapered case so if you are backed off slightly from the shoulder the case will expand down the length of the case until the thicker brass at the base of the case stops the expansion. That's why I asked about the shoulder and overall length.

You really need to back off on that powder charge a little. That primer looks very flat. You should start your loads just about the minimum or at least 5-10% below max and then slowly work up from there. There are so many factors the can increase chamber pressure it's better to be safe than sorry, especially with a new build. Seating depth, case prep(chamfering) and crimp, if used, can be major contributors to chamber pressure.