Just to add some more to this. Clausewitz stated in his tactical treatise that the 'effective range' of muskets began at 300 paces. And that was for volley fire. The many ordiniance tests scored out to 250 yards or more, which would be a waste of time and money if no one fired at that range. The observation that French skirmishers were firing at 150 yards or greater is fairly common.
A friend of mine who fires black powder muskets has a brown bess that he has used with British 1806 ammo [powder and shot weight]. He found that he couldn't hit a 4 X 4 foot target at 150 yards even one time out of ten. He then thought to wrap the ball [or kept the ball] in the cartridge paper when loading. Once he did that to reduce the windage, he could hit the target seven out of ten times. He was amazed. I seriously doubt that such things were lost on the Napoleonic soldiers. Considering how much time and effort was put in determing 'the pace', measuring it, determining distances for march, evolutions and musketry, I doubt that the range estimations for an experienced officer were all that far off.