I'm sorry if my last comment upset you.
You seem to have accepted that ( your words ) Chairgun, Rifleman's, Improved-Rifleman's, Sierra approach and other computer modelling are all wrong.
Championship winning shooters are wrong.
It's probably bendy barrels ( less than 2 feet long and probably 16mm thick steel ) being affected by the extra gravity of raising the barrel a few degrees.
It maybe your gun.
... but there's no chance it's you.
Crack on fella.