Does the .40 S&W still have any ass left by the time it has traveled 500 yards?
The first time we tried this, we used 55-gallon drums for targets. The .40 bullets went through both sides with no problem at all.
That has to be the flattest 500 yard trajectory I have ever seen for a gun fired at 500 yards. Based on the image with the rod showing the trajectory through the barrel, it is virtually flat/parallel to the ground.
Considering the amount of drop at that distance, there is no way the holes indicated could have been formed by a single shot fired at 500 yards.