History, as presented on TV, usually isn't.
Since you are knowledgeable on the subject of guns, you caught a series of incorrect statements and knew them to be untrue.
Now think about all of the programs you've watched that told you about stuff you didn't already know something about. Those programs were also filled with errors, but you couldn't catch them.
The only way to really learn something is to read, or listen to, or watch, at least two competing authorities, and then to compare and contrast the things they wrote or said, looking for inconsistencies.
When you have settled the inconsistencies to your own satisfaction, then you really have learned something.