More like the .30 shoulder is shorter than the 7mm - just slightly. Better than the other way around.
When you chamber the shorter .30 into the longer 7mm chamber and fireform, Bada-Bing!
The case length is the same.
I use bushing dies to neck down in two stages.
I internal ream to remove the donut build-up, then neck turn.
My neck TIR is .003 - .005"
I have not annealed yet after two firings of 250 cases I spent all winter prepping. I have the tools to anneal, just haven't done it yet.
I am not pushing the bullet hard, a 180 Berger VLD-H @ 2780 fps with RL-25 in a Surgeon Scalpel 26" Krieger.
Accuracy is superb at .2 MOA.
I just got my hands on RL-26 and will be working a load that will get my FPS up about 130 fps.