Weapons of the time were notoriously inaccurate at long range of 50-100 yards. The closer they got to the shooter, they more likely they would be killed...................
Definitely. And due to the give-em-the-bayonet when you get there formations, the closer they got, the wider the target. Don't waste shots. OTOH, to maintain more or less continuous fire, the professional armies of that time also had deep ranks. And clearly they had iron discipline to walk into the teeth of fire like that. If concentrated fire (the whites of their eyes approach) knocked down enough of the redcoats to make them break for their original position, great. Not a good idea to get involved in a hand-to-hand struggle with a body of pros though.