A buddy was in front & a little to the side when an Abrams let loose with its main gun. He lost consciousness.
Guy I used to work with was doing some kind of work at Ft. Sill as a civilian contractor when he drove his vehicle in front of some artillery just as it fired. (Never did find out who was at fault - him for being where he wasn't supposed to be, or the arty guys for not marking the road as off limits for the exercise.)
As I recall him telling it, he was 100 yards or more in front of the gun, and says the concussion could really be
felt rather than heard . . . the shell passed 'way above, but the driving band came off the projectile (They're not supposed to do that, are they?
) and spun across the road in front of him. If
that had hit the vehicle he was in, the result would have been . . . bad.