@Victork2 I can only speak to my experience and I am pretty sure that this is how the Brit Army did it as well. Maybe the US does it different. From an âetiquetteâ POV, as a gunner the TC outranks you. so you had better follow orders lest you find yourself on an insubordination or âfail to follow a lawful orderâ charge 
From a training and doctrine POV.
The TC selects the target and gives the order to fire⌠Always
The gunner may have spotted the target first, quite often this was the case because the gunners sight on the Leo AS1 was far superior to the TCâs (no hunter - killer capability).
So, for example, I am scanning for targets and see one - . Say I saw a T-64 and a couple of BMPâs I would probably lay onto the tank first and say âT-64, ONâ. But, the TC may override that because the range might mean the BMPâs ATGMs would be the greater threat. From there it is as if the TC had seen the target first:
TC: âSABOT, T-64, ONâ
Gunner: âONâ Even though you had aleady said that, and this is when I would lase and relay.
Loader: Pulls a SABOT round from the ready rack, loads it, grabs a second round and âcradlesâ it, hits the Make/Break button and says âLoadedâ
TC: âFireâ
Gunner: âFiring Nowâ pull the trigger on the now.
Because this example is a SABOT engagement it was what was termed a âcommanders shootâ. Even though as gunner you would call âTargetâ for a hit, he would call any adjustments (e.g. aim top edge) and give the order to fire for every round. As the gunner you only did what the TC ordered. The loader would keep loading SABOT and reporting 'Loaded" until the TC said âStop, target destroyedâ.
With HESH, HEAT and Co-Ax; it was a âgunners shootâ. Once the initial order to fire had been given I would call out âTargetâ or apply any corrections (e.g. âleft half target, add 4â (mils)), and fire everytime the loader reported âloadedâ until the TC said âStop, target destroyedâ⌠or rarely âStop, relase, relayâ due to the engagement taking longer than a few rounds and this was necessary and then âGo onâ
