Calibre also matters I guess. 25mm rounds having more accuracy due to higher velocity.. the same goes for the GSH-30 on the Russian hardware.. apparently its accuracy made the Russians limit the number of rounds.
Am going to pose this only as speculation and an intellectual exercise.
But first...Why do we want high cyclic rate of fire, especially at moving targets ? Simply put, we suck at guesstimating where this moving target is going to be. It does not matter if the target is an aircraft in 3D space, or a deer running on the ground. It takes training, time, and often innate skill to make an excellent marksman. In gunnery, leading the target is always a learned skill, not something one is borned with. We attempt to quantify every aspects of this skill and continually refine it, whether it is to teach the human soldiers or impart it to the machines. So the reason we want a high cyclic rate of fire is because we want to deposit as much materials on the target as possible within a certain time frame, preferably as short a time frame as possible as well.
What if, for speculation's sake, the F-35's gunnery software is capable of this skill and does it at a high level due to the sophistication of the aircraft's sensor package ?
The sensors, active and passive, sees the enemy fighter ahead and calculate, with less than one meter precision, speculatively speaking, where the enemy fighter is going to be. The gunnery software calculate that based upon the target's predicted path, the gun will need to expend 10 rounds -- as a packet of material -- at that predicted spatial location. The F-35 pilot does have the option of shooting more than 10 rounds, of course, but he chose to let the gunnery software control the amount of munition. All he has to do is make the final decision to kill, which means to squeeze the trigger.
Say that out of 10 rounds, only four hit the target. But now the enemy fighter is damaged to one engine. Since the enemy fighter have widely spaced engine placement, he now have asymmetric thrust, which strains his flight controls in trying to keep stable flight. Damage to one engine also mean diminished hydraulics, which may lead to limited maneuverability.
As the enemy fighter struggles with its wound, the F-35's gunnery software now predict another 10 rounds, and the pilot shoots. Since the enemy fighter is already limited in maneuverability, 8 out of 10 rounds impacted.
The WW II era Japanese Zero fighter have two 20 mm cannnons. The American fighters heavily favored the .50 cal machine guns.
MK 108 cannon - Wikipedia, the free encyclopedia
...excellent 20 mm MG 151/20 required an average of 25 hits to down a B-17.
For our speculative air combat between an F-35 and an enemy jet fighter, 12 rounds of 25 mm cannon gunfire should be enough to at least send the enemy fighter home, if not outright compels the enemy pilot to eject, thereby denying the enemy a valuable combat asset.
Again, am not saying that is how the F-35's gunnery software works. Am just tossing a speculation out and let people make up their minds.