If I may be so bold, we have approximately two generations of legacy thinking being explained here by some very well informed people.
In modern BFM, which 'legacy mindset 2' thought would never happen due to all missile load outs it is a completely valid tactic to remain within the enemy Rmin and possible if you have the g, alpha and power available. Both players will also be ensuring that, in a defensive situation they present the hardest 'Range/Angle/Closure' problem possible - which will probably differ significantly to WW2 era bombers or those of the V force, as experienced by those of 'legacy mindset 1'.
This leads you to what will one day be known as 'legacy mindset 3'. You aren't realistically in contemporary BFM going to track the opponent, but you need to have the gun site up at all times for anytime you can't shoot due to Rmin or acquisition problems. If you have a radar that gives you a decent aiming solution so much the better. Close scissors at base, slashing opportunities are all great times to use a gun, and don't forget - every 180 by zip is a guns opportunity, as is every time he flashes through the HUD, it's just that we aren't allowed them in peacetime!
Last point, it was very interesting how the RAF entered WW2 without a clear understanding of the damage mechanisms for A-A gunnery which led to small calibre armament. Don't forget though, in 'soon to be legacy mindset 3' the aircraft have a lot less space, are made of materials that aren't necessarily easy to repair and have a lot of vulnerabilities past pilot, controls, engine. Look at the damage a pebble can achieve in a gas turbine, a single shell could be all it takes.
Just trivia but with the M61A1 you could choose your rate of fire.