Just how slowly does that bullet travel down the barrel? Or is this the revolver version of that (fairly) recent movie whwere they made the bullets curve around things to hit who/what was behind?
I'm not even a real physicist, let alone a theoretical one, and I can see the report is high-grade BS.
If the piece was calibrated for heavy bullets I would have expected to see the sight blade set to be a skosh low to allow for bullet drop. But just how much drop are you getting at 30 feet?!? That's more an artifact for long guns at much longer ranges.
But none of that will effect the bullet meaningfully between ignition and leaving the barrel.