I'm a mechanical engineer, by training, visualizing the trajectories of both the bullet 'cloud' and the fighter pilot are pretty much automatic for me. I also looked up the muzzle velocity and velocity decay factors.
While I don't know the training or fighter piloting, I do know the physics and dynamics involved.
Draw your own conclusions as to whether or not I'm qualified to make the statement I did.
As this is a special interest of mine I'd like to read a better explaination of your theory as the one you posted was not in the realm of being probable.
Please, explain the velocity decay factors, especially as it relates to the variable ballistic coefficients of projectiles and the effect upon their trajectories.
The facts related to the ballistics of projectiles fired from cannons show that a jet could not simply reduce it's elevation relative to the position where it fired it's cannon and reach the speed necessary to catch the projectiles while maintaining level flight at the reduced elevation as you postulated.
Reading the article and the explaination, the most probable scenario was presented. The one you presented isn't probable to the point of being nearly impossible.
A projectile fired from a firearm or cannon immediately drops relative to the line of bore unless the line of bore is perfectly 90 degrees to the force of gravity and we can discount that because that too is nearly impossible in this situation.
One does not visualize projectile performance, it can be calculated and in fact is within fire control systems using cannons.
What did happen is that the point of aim being above the line of bore requires the barrel be adjusted (moveable or fixed) to allow the point of impact and point of aim to coincide. This happens at two distances past the end of the barrel.
As the projectile follows it's ballistic trajectory it is possible for an aircraft in level flight to fire it's cannon and if the velocity of the aircraft can increase enough it can catch the projectile as it (projectile) crosses the second point of aim continues downward and reaches the second point of impact so long as the projectile's position is within the envelop of the space the aircraft covers. In essence, the aircraft would not have to reduce it's elevation if it could increase it"s velocity enough.
It's actually a very simple appearing curve that shows the projectile's arc (trajectory) but the varying ballistic coefficients insure it is not something a person can visualize, it must calculated or guessed.
The calculations are facts, not opinions or visualizations. Those here who have been trained to employ precision weapons fire, be they firearms or cannon know about this and also know the many variables that affect the trajectories.
Therefore, the scenario you present is improbable to the point of practical impossibility, that being the jet would have to lower its elevation and fly level to catch the projectiles. If the barrel of the cannon was so inaccurately adjusted that could be possible but then that would explain the description of the event the military provided, that it happened as the jet was climbing.
If the projectiles were fin stabilized, then all bets are off.