I've also read many times that the British fought using the same tactics that were in use on the European continent. In quite a few of the battles both sides fought using about the same tactics. But the colonists did have a tendency to seek cover and melt into the forests. Unlike The European plains, America was mostly densely forested east of the Mississippi. Also the Americans were accustomed to fighting American Indians and adapting to their tactics. Even the British soldiers would learn to use cover in the crowded forests.
Exaggeration was/is common in recounting claims of "amazing" shots. Truly, the American riflemen were masters of their craft and nothing like the average recruit who had to be trained with a musket. One would naturally be a master of the rifle if having been raised with this state-of-the-art technology. I remember "seeing" a few deer, and two enormous bucks, at a distance of 400 measured yards. I qualified the word seeing because I only saw occasional dots in the open pasture; and them would lose them until they moved again. But viewing them through a friends Military binocular confirmed it in fine detail. I would have passed on a shot with a modern scoped rifle, not to mention iron sights. 200 or 250 yards sounds quite plausible for a traditional Flintlock with a really good shooter. Back then and today we've had/still have many shooters with such skill. I'm just not even at the periphery of these amazing shooters.