In theory and in test, the Vulcan cannon round in the F-16 is lethal out to 1 km range. However, in practice, close-in maneuvers would take combatants inside that 1 km radius and even as close as WW II type dogfights.
The only time any pilot would have to get within visual range is when a situation was created from an environment where missile use is restricted.
- Air Dominance. The ability of an air force to compel other air forces into subordinate postures.
- Air Superiority. The ability of an air force to achieve control of contested airspace and repeat if necessary, and if there are losses, those losses would not pose a statistical deterrence to that ability.
- Air Supremacy. He flies, he dies.
Air dominance is when/where even the mere presence of a powerful air force is enough to compel other air forces, allies and enemies, to at least prepare plans for rearrangements of where each is in relation to this powerful air force. This situation is usually before or after all the shooting are done, and the odds of having the need for within visual range identification before combat engagement -- just in case -- is high. An unidentified flyer maybe a noncombatant.
For air superiority and air supremacy, this is where contests and enforcement of control are absolute. Anyone in this situation must be able to identify himself in complete clarity because the contestants/enforcers are free to engage from as far away as possible. The need for within visual range identification are not discarded, just very low odds of that happening.