Occasionally I read about 45/70 revolvers made by machinists. Elmer Keith shot one. There were huge numbers of WW2 veterans who were trained in the service for maintenance activities, and many of them made rifles and pistols. I think it possible that this pistol is one of these, based on a Ruger Blackhawk with a Colt Dragoon trigger guard.
I hate the squared off trigger guard on my Super Blackhawks, the thing takes meat off my fingers. Stylistic yes, practicable, no.
A small camera lense will make the barrel look curved. Been there, done that.
People with too much time on their hands do crazy stuff!