I know this news is somewhat old, and my explanation may be long in the tooth for some, but we can only hope that this court decision stems a bit of the tide of the runaway Regs change(s) by the ATF.
I have a background in Federal Law. Albeit only Title 26, Subtitle(s) A-C. In layman's terms that's Income Tax, Estate and Gift tax, and Employment Tax. Yeah, I used to be and actually still am a 'bean counter'.
Of note here is much of the firearms laws are in Subtitle E, Alcohol, Tobacco, and certain other Excise Taxes.
The intricacy of Federal law to 'attempt' to keep it "Constitutional", is a great big paper tiger that takes some finesse to decipher. Now, for all the subtitles of Title 26 that I was versed in, it went like this:
You have the U.S. Code. The agency enforcing (IRS in my case) said 'Code' writes regulations that are published in the Code of Federal Regulations, or CFR for short, that gives their (watered down) 'interpretation' of said code. Then the IRS writes their Publications which interprets the CFR further adding or subtracting what they wish on the way.
The ATF, also being a branch of the Treasury Department, obviously does the same. And they seem to use really great latitude in their 'interpretation' of the U.S. Code whenever the whim strikes them. But here, we can hope that the courts are going to reel them in. I mean, even the IRS doesn't make sweeping changes via the CFR like the ATF does.