Based on pics it looks like a rifle that's not legal in DC due to it having too many features, and probably the named/clone ban.
Being from Atlanta I presume the fellow did not take the 16 hour class to put in for a DC carry permit, which doesn't let you open carry or carry on the mall.
That's a felony for the firearm, carrying it, one for each bullet, and each magazine over 10 rounds.
I actually fully expect many of these laws to be struck down, eventually, as they are pretty clearly in violation of the new tradition scrutiny brought on by Bruen. Heller is probably already gearing up for it lol.
What I expect to stay is stuff like the ban on the Federal areas like the mall, as it would likely fall under the "sensitive places" allowance. It will be interesting to see if the Washington DC ban on carry in any place that holds an alcohol license covers that, however.
Personally, I think that if you set up a gun-free zone you should actually fence/wall it off and have security to ensure it stays that way. All the federal areas that prohibit carry are already 2A and 4A free zones, so it's not really a stretch to move from "you may be searched at all times" to "you will be searched every time".
If we are to look at historical tradition, banning concealed and open carry would be okay, registration would be fine, regular inspection would be fair game, and requiring an oath to the government would be fine since all of those were common when the 2nd Amendment was passed. However, I don't expect the current Supreme Court to consider that aspect though since they clearly cherry picked tradition on abortion rights and referenced a Witch Trial juror to back up their view instead of someone more relevant like Ben Franklin who wrote about common abortifacients and how to use them.
Schenck v. United States in 1919, which held that the defendant's speech in opposition to the draft during World War I was not protected free speech under the First Amendment of the United States Constitution. The case was later partially overturned by Brandenburg v. Ohio in 1969, which limited the scope of banned speech to that which would be directed to and likely to incite imminent lawless action (e.g. a riot).
The Court held that the government cannot punish inflammatory speech unless that speech is "directed to inciting or producing imminent lawless action and is likely to incite or produce such action".
The Court held that the government cannot punish inflammatory speech unless that speech is “directed to inciting or producing imminent lawless action and is likely to incite or produce such action”.