ATF busts shipment of airsoft guns--said they can be converted to machine guns?

[publius42]

So essentially these Airsoft replicas cannot even operate an AR15 trigger pack without heavy modification with a precise tooling system operated by someone who knows the specific measurements to drill and tap the WE TTI lower receiver.

If something a machine shop can turn into a machine gun is "the same" as a machine gun, why are AR-15s not banned under the same logic?

And why don't machine shops have to have FFLs? A reasonably talented individual can design and make his own version of a Sten gun for his own use. Of course, that would be interstate commerce, like most everything else, but he could.