DC is not gun friendly.
To own one you have to live in DC , register it and pick one from a very restrictive list [No ar-15's for example, no pistol grip shotguns, no tactical stocks, etc etc..]
If you buy it new it has to be sent to the only FFL [Mr Sikes, who is a nice guy] in DC.
You have to pick it up etc at the main police hq. You will be photographed, fingerprinted, and subjected to a 10 day FBI background check.
1- Firearm per month.
Registration must be renewed every 4 years.
You may only transport the firearm [once you pick it up] directly home, or from your home to 'approved' activities, [basically -- out of DC] and then back home.
As a non-dc Resident, possession of a firearm in DC would be technically illegal unless you are a LEO or some other exempted entity.
Once you are a registered owner of a firearm, you can possess any ammo [the law was recently changed, as it used to be 'only for your registered firearm']. The 'spent casing' guy had an issue I believe with domestic violence or a protective order, either will restrict your ability to own firearms for up to 5 years.
I am a newly registered DC gun owner, the steps I had to take only took about 2 weeks, and this was over the christmas/newyears holiday break, while they were relocating the Firearms registration office from the first floor to the 'third' floor [I think]. So I am not familiar with the difficulties the famous reporter for the Washington Times had, however I think she may have tried to register before they had fully implemented the law, or possibly exaggerating her issues [although since I have never tried to register a firearm outside of DC, I'm not aware of how much easier [relatively speaking] it may be in other jurisdictions.
YMMV