Back in the day when I was at USAO-DC, I went through the motions of registering a firearm in WDC. I didn't actually register a gun, but I went through the process as if I had actually bought a firearm and was registering it. I had to fill out the form, which asked me where I would use the gun and keep it. I took it to the office when it was open, which were very limited hours during the business week. Since I was USAO-DC and only going through the motions, they opened up especially for me! To say the least, it was a pain in the arse to "register a gun", which means even "law abiding citizens" don't do it. Quite a few just keep their guns broken down in a case without registering them.
With this new decision, does it mean that some of the requirements of registration, such as belonging to a place to shoot the gun, the requirement that stored guns can be inspected, and so on are reasonable? I like how DC used to only register .38 revolvers with 4" barrels. Will that be the law, only handguns of that description are registrable? Can the district charge an exorbitant fee to register a firearm?
One provision of DC's Firearms code is that anyone who wishes to legally own a firearm must register it, which I assume has not been overruled. Any gun which cannot be registered must be removed from the District, or otherwise disposed of, in a period of 10 days to 2 weeks.
Some victory for the RKBA!