This is taken from Arnies front page right now.
http://arniesairsoft.co.uk/news2/
All I can say their definition of easily convertable is...NOT easily IMHO.
For those who want to make it here's how without reading through:
WE or WA or JG M4 GBBR
A Complete Upper Assembly w/ bolt carrier
AR-15 Hammer Set, Pin Spring
AR-15 buffer spring and buffer
a Steel rod to replace the pivot pin (its not a direct drop it)
A dremal and some sanding work..
=They say 1hour
OR if you want to do it the easier way...
Straw Purchase an AR-15
Remove the Trigger Assembly, sand off the disconnector (DON'T ASK ME WHERE, I know where though, discovered this accidentally when I wore out my GBBR disconnector)
= I would say this would take ~15min for a newbie, 5 min for a gunsmith.
Seriously wow, those ATF are really that desperate. I bet Wendy Cukier is gonna use that as a knee jerk reaction to ban all pellet, paintball, nerf, airsoft, paper, lego, chicken-leg-resembled gun