This is one of those "oldie but goodie" movies made years ago, and shared with me recently by a retired US Army officer who worked in the Army's medical corp.
It is a comparison of historic firearms to modern rounds, demonstrating ballistic performance through ballistic gel and bone. The movie features Civil War era weapons and runs through up to and including the 5.56 NATO round.
I cleaned up the video and audio as best I could and added my friend's comments at the end.
I think you will find it really fascinating.
LINK TO VIDEO