Measuring the case length identifies this problem. Trimming the neck is the solution. The shoulder does not need to be pushed back.

This is a problem that should have never been if proper measuring had been done. The fact that it was spotted by a chronograph was a happy and lucky event. Experienced loaders always measure and trim as required, and would almost certainly have spotted the normal pressure signs without using a chronograph.

The thing that I take from this is to make sure that when you ask someone to help you learn to reload that they actually know something about it.

I have been using chronographs for many years. They are a valuable tool for measuring velocity and SD, but they are absolutely not necessary for a beginner that is trying to put together a reasonable kit for $250.