Now I'm gonna post about that Prussian experiment I mentioned then ramble a bit. Let's start with a quote from the book:
"John Keegan and Richard Holmes in their book Soldiers tell us of a Prussian experiment in the late 1700s in which an infantry battalion fired smoothbore muskets at a target one hundred feet long by six feet high, representing an enemy unit, which resulted in 25 percent hits at 225 yards, 40 percent hits at 150 yards, and 60 percent hits at 75 yards. This represented the potential killing power of such a unit."
This experiment shows how accurate were these rifles (well muskets, they weren't rifled) in the trained hand of the Prussian line infantry. A musketman of the era could fire 4-5 shots per minute, but let's say just 4. This would mean a unit consisting of 200 men was capable of inflicting 480 casualties per minute from about 70-75 metres. This also means they could have obliterated a same sized unit under 30 seconds. Battles should have concluded in an minutes.