Found in Reddit:
IIRC, your average 9mm, 124 grains rides around 1,100 feet per second or 750 miles per hour. If you go 9mm +P, then you start hitting the 830 MPH mark.
Oh yes, the speed of sound is 767 miles per hour.
Right now at you local WalMart they are selling BB pistols that deliver twice the speed of the assumed guns in the photo, no background check required.
Somebody confused their Guns and Ammo with Car and Driver.