Whatever is at the end of the barrel looks metallic. There is no blur, so I assume it is not the projectile.
What type of camera would be necessary to freeze the action of a shotgun discharge to capture the projectile? Shutter speed?
In a very controlled enviornment that is possible. This is outdoors and appears adhoc.
It is (if real) one frame of a very high speed camera series that could also display the charge leaving the muzzle.
Such a camera is used on Myth Busters to display shooting results. It appears as slow motion