Not a cellphone or shred of hearing protection in sight, just a group of boys living the moment.
In aerial gunnery, gun harmonization, convergence pattern, convergence zone, convergence point or boresight point refers to the aiming of fixed guns or cannon carried in the wings of a fighter aircraft.
The wing guns in fighters were typically not bore-sighted to point straight ahead; instead they were aimed slightly inward so that the projectiles met at one or more areas several hundred yards or meters in front of the fighter's nose. The intent was either to spread the fire of multiple weapons to increase the chance of a hit, called "pattern harmonization", or to concentrate the fire to deliver greater damage at one point, called "point harmonization".
A drawback of harmonization was that guns worked effectively in a limited zone, so targets closer or farther away from the zone were not damaged as much, or were completely missed. The rounds would diverge further apart after passing through the convergence point.
