Hello Chino, good to see you around in the forums (being a fellow infantryman). If you don't mind, I'm going to qualify what you mentioned, just a little.
I feel that the "double tap" has its place in urban warfare and is a very valuable tactic, if a solider is properly trained to apply it.
But you are right, the hypothetical scenario you described does not require the "double tap".
I believe what we learned in our prior infantry training modules (FIBUA/CQB), is by now outdated. Back then, we were essentially trained to clear rooms with our weapons (be it M16/SAR 21/Ultimax) in auto mode. This old style of training is not suited for modern COIN operations, where the insurgents are intermingled with the population. The use of this tactic (back then) was a result of the limitation of our infantry shooting syllabus. A 5.56mm auto spray into a room may kill all the occupants of a room. If you have intermingling of civilians and insurgents, not a good outcome.
The old methods that I used to teach my men for marksmanship syllabus training is inferior to reflex shooting style that the 4 SIR boys were exposed to in Alaska, when they were sent for training in the US with a US Stryker Bde.
In fact, our hostage rescue teams (HRTs) also use reflex shooting. From this base, they then progress in their training to the kill rooms. At the kill rooms, the "double tap" is frequently used, to enable discrimination between insurgent and civilian. However, the ammo of choice is often the 9mm for the HRTs.
The old urban infantry tactics we used were more a reflection of the limitations of our shooting syllabus (that I used to teach). Looking at the new urban training facilities, with video playback, the current SAF infantry trooper's tactics in an urban fight, are miles ahead of what us old timers were trained in.
BTW, I was also trained to use the GPMG and the 84MM RR. While the 7.62mm GPMG is a full auto, we used trigger control (very simple, just intermittent firing) to conserve ammo and to avoid overheating the gun (which will result in a run-away gun). It gets quite freaky when GPMG barrel gets too hot from prolonged fire support. We try to do a barrel change before we get into a run-away gun situation.
Note: Run-away gun occurs when the barrel of a GPMG gets too hot. Essentially, even if you don't squeeze the trigger, the gun keeps firing because the rounds have cooked off upon entry. The only way to stop the gun from firing is to cut the ammo supply (i.e. break the chains, since the GPMG is belt fed).
) center mass. A double tap on semi allows 2 shots to be rapidly placed in roughly the same spot on the target without allowing recoil to completely blow your aim. The problem with 3-rd burst (on an M16/M4 at least) is that the 3rd round often ends up sailing over the target's shoulder. I wouldn't mind seeing 3rd burst replaced with 2rd burst setting - especially if the ROF is super high to get a sort of an "auto" double tap 2 rounds 1 hole feature.