When the supreme court shredded a New York gun control law last year (a law that had stood for a century), their reasoning was unless a gun regulation or something very similar to that regulation was already in place at the time the bill of rights was written, then it is not allowed based on their interpretation of the second ammendment. As the dissenting justices pointed out, this of course, is crazy, and if actually applied like how they said it would invalidate pretty much any gun control we still have that hasn't been taken away already. And isn't similar at all to how we look at standards for other things in the bill of rights.

So honestly the fifth circuit is probably correctly applying this reasoning here, and many gun laws are in court over this new standard. This was a standard created by the Supreme Court last year though, the fifth circuit didn't pull it out of their ass this time. But like any of this "originalist" nonsense they aren't gonna apply it consistently, just when it suits them. I would expect the supreme court to let this law stand this time to avoid yet another very unpopular decision highlighting their extremist second amendment interpretations, even though it doesn't live up to the ridiculous standard they created last year. Expect them to start applying that standard again capriciously at any time though.