Sorry the photo is so bad but I can't figure out how to take barrel photos.

What I'm hoping this shows is the two "steps" inside the chamber. The first step is the shoulder step and the second step is the rifling although that doesn't show at all in the photo, the step does, the rifling does not.



Each step appears to get smaller. There is no compression ring that I can see that makes the bullet smaller before it hits the rifling.