There were only two minor mistakes. First, Daniel Morgan did not lead the First Pennsylvania Infantry. He was only a captain in it. Second, W. W. Greener was the first inventor of the expanding bullet. Other than these trivial points, the author has a very well researched and written article.
http://warfarehistorynetwork.com/daily/military-history/revolutionary-war-weapons-the-american-long-rifle/
http://warfarehistorynetwork.com/daily/military-history/revolutionary-war-weapons-the-american-long-rifle/