If I were to estimate I would say I was aiming above the jug about 3MOA
not impossible at all, but aiming 3moa high, the bullet would strike the ground 300 yards before it got to the target.
you would actually need to aim about 15 feet high, at 500 yards with a run of the mill 30-30 load.
actually , with zero wind, and 75 degrees, and 29.5hg barametric pressure, (avg spring day) yielding an Atmospheric Density of 0.07418 lb/ft³, the bullet would have dropped 155.2 inches into the jug, taking over 1 second to get there, and will have dropped below the speed of sound about 20ft before impact.
its an unbelievable, but certainly physically possible shot.
i could probably do it once with 3 20rd boxes.
ps. i take that back, my eyes aint what they used to be.
i do know a korean war vet with incredibly sharp vision for his age that could probably hit it 4-5 out of 8 times with his garand (the most amazing international harvester m1 ive ever seen)
at any rate, with a 30-30, it incredible, and i will leave it at that.