Ry points out:
The April 2009 edition of the NFA Handbook has removed pin & weld from the methods that are allowed to extend barrels to the minimum (16″ rifle, 18″ shotgun) length to avoid paying an SBR/SBS tax.
And asks:
What happens to the millions of barrels out there that were pinned and welded?
It's possible that 100s of thousands of criminals were just created by a simple regulation change without even a whisper of notice in Congress. Is it tin-foil hat time? Or are they really out to get me?
Ayn Rand indeed.