You couldn’t possibly believe that.

Sniper rifle accuracy is described as the size of a group at a certain range, or more often a ratio of size vs range. MOA or minutes of angle roughly equate to about 25mm at 100m, or 1 inch at 100 yards. A group of 5 shots that are less that 25mm at 100m range would be considered sub MOA accuracy. An AKM with good ammo could make 2 MOA, while an average AKM with average ammo would make 6 MOA or worse. (obviously this gives an estimate of impact spread at larger ranges but that does not necessarily hold true… a sub MOA rifle might not even print on the paper at 1,000m.)

The point is that a 0.75 MOA rifle will record impacts in a cone of a diameter of 0.75 MOA. Other than that there is no pattern or curve that can describe how the projectiles make holes in the target… just that with a good shot, good ammo and maintained rifle the projectiles should hit within the circle. Replace the rifle with a water cooled twin barrel 30mm cannon and it will also have a cone of fire where the rounds will impact. This cone is effected also by the accuracy of the drives aiming the cannon (moving target) and also by the accuracy of the location of the target and in tracking the targets future position and laying the guns to follow that position. The muzzle sensor will update the computers as to the velocity of the shells to improve accuracy and the guns themselves may already be toed in or able to be toed in to concentrate their bursts for some targets at particular ranges but the accuracy of a gun that fires from a locked position that uses the gas from its shot to reload the other barrel suggests to me a much more accurate setup than a gatling barrel that moves contiuously. If the Gatling gun was the best idea the Soviets have plenty of gatlings in 23mm and 30mm to choose from when the tunguska was designed.

(You should also remember that both Tunguska and Pantsir have 8-10km range missiles that are equipped with proximity fuses that could also be used against small targets if necessary so even if the guns couldn’t engage a mortar shell the missiles certainly could.)