I recently mounted a Bushnell Red Dot, sighted it in and proceeded to shot a couple dozen slugs. It is mounted with a B Square saddle.
After removing the barrel to clean the gawd awful mess left by the slugs, I put things back together.
Yesterday I went back to the range to shoot more slugs. I was about 10" off the paper.
Did I loose zero by removing the barrel? I'm pretty careful handling the shotgun - there were no bumps or bangs or drops. Everything is tight - nothing in the mounting arrangement was loose. The barrel seems to fit the receiver well - there does not seem to be any movement between the barrel and receiver.
So, what happened to lose zero?
Thanks for taking the time to share your experience and insight.