This is the Gun Parts Trafficking Act of 2001 introduced by Robert Torricelli (d-nj). It seems that this typical eastern pile of feces wants to prohibit and ban shipping or transportation of firearms parts, and when you read the text it would make it illegal to reassemble your own firearm after it has been disassembled for cleaning.

The second page says something about taxes when manufacturing fire-arms, and a license to do so.
I'm just a simple Dutch taxlawyer, but it seems to me that for a private person to be allowed to build his own gun from kits and/or parts a tax of $500 (now $50 for a manufacturer)will be levied. The fact that you may then build as many rifles (probably within a year) as you like seems to be of little solace.
For al you US-(AR15) private-gunbuilders I hope I'm wrong !!!
Taxation has been known to be (ab-)used before !BTW there is a link to the matter on the Olympic Arms website.

Hans