The ATF is apparently working hard to define manufacturing as touching a tool to a gun. Gun Law News has the skinny on the continuing war on gunsmiths:
The BATFE is going after gunsmiths for work analagous to this via the Tax and Trade Bureau to fine, and in some cases, close down small, custom gun shops.
…
Nowhere does “Make a bad gun good” or “Make a good gun better” fall anywhere within the definition “manufacturing firearms”. That does not stop the BATFE from throwing common sense out the window.
Ultimately, the question for gunsmiths becomes, “Where does maintenance end and manufacturing begin?” The question is significant as the answer affects whether or not you pay Federal Excise Tax on your work. Get the answer wrong and you rate a visit from the BATFE and the Tax and Trade Bureau. Unfortunately for some smiths, the answer changes depending on which BATFE agent you talk to.
If you thought that was bad enough, be patient. Let’s say that you are a gun writer. As a part of your job, you have had gunsmiths tune guns to your liking so you could write about them, thereby making money on the improvements. According to some in the BATFE you have just made yourself a ‘manufacturer’ and the smith working for you is a subcontractor. You, as the writer, are responsible for having a manufacturing FFL and paying excise taxes.
Yeah, the ATF needs it’s collective pee-pee whacked.