[OneWingedShark]

>> "What is the difference if I held this lower receiver for two hours and then asked my brother if he wanted to buy it?"
>
> Because the federals want to know where each and every gun is so when the SHTF they can target the individuals who have means to oppose them.

They already have the tools to do most of this; the NSA's data-/communication-harvesting, combined with the IRS's access to financial records/assets, and the FBI's social-network mapping (see also this)

And remember the bonus army when people say it can't happen here and American troops won't fire on citizens.

[Durus]

Don’t forget the converse either. The largest military organization in the world tried to pacify America once before and it didn’t work out too well for them.