https://www.youtube.com/watch?v=6m8Y6ZmSBiU&t=330s
This guy answered- "Interesting test John. You mentioned that you thought that the bullets on the rounds that were really out, could have been pushed back further into the case. Food for thought, the bullet could have been pushed more into alignment by the chamber as the bolt was closed. Regardless, it was a very interesting test. Thanks!"
I have often asked myself this ?
I watched this and have no idea, I am sometimes in wonder at how much I do not know.