I heard that John Bivens made two rifles accurate to the period but the director said' No its too short ' So they hung in the office & others more to His idea got made . No idea now true this was but seems plausible
Daniel Day Lewis played Hawkeye in
Last of The Mohicans using a completely wrong pattern, flintlock rifle. I actually wrote to the builder and got a reply. He made what was ordered by the production company. He would've put a propeller on the thing IF they had ordered it.
I've been involved in several TV productions using muzzle loaders. The directors do whatever they think is "cool" in many instances. In the swamp-ambush-scene in
The Patriot, where in the aftermath they discover Cornwallis' personal effects and two dogs..., and one character says, "I say we drink the wine, eat the dogs, and use the paper for musket wadding...", the director wanted the ambush to start with the Rebels COMING
OUT of THE WATER after having been fully submerged, like "Navy Seals"..., and the director was quite miffed when he was told the muskets can't work if they do that. The scene as shot shows the Rebels hiding behind trees in the swamp, then coming out from behind the trees to shoot.
A director, even one doing a historic drama, often knows very little about the history and even less about firearms. Another good example is the TV series,
Jamestown.
LD