I think it's possible, but it isnt the part that concerns me most.
I'll tell you bigest complaint in simple terms.
Say I buy a cut up 50 yeear old rifle kit, I mean cut in the middle with a huge saw, no use, not workable at all, crusty and wore out usually. But interisting historicly, and I can refinish it and make it pretty again.
People like to do this kinda thing. Nothing wrong so far, right? Now. The part the big saw attacked and distroyed, that was the "heart" of the rifle, usually right in the middle and everything else bolts to it. Now for a modest ammount of money, I can buy a nice legal canter section, one that is engenered in such a way that it's usually not easily to make it into the dreaded full auotmatic, which is another issue in itself. Now I get my shiny new center section, known as a reciever, and I have the tools and skill to assemble the old parts from my kit, which I have cleaned and refinished to a nice color, but wait! I have to take a certain number of parts, around 7 or so, and replace them with the EXACT same part that's been manufactured in THIS country. Now there are a number of problems I have with this as a free man and as a technician. The main one is that the before mentioned reciever is almost always not of the quality as the original, requiring hand fitting and filing and many hours of attention to make it work at ALL, not to mention safely. Then the same problem applies to the US parts I have to replace, being that we cant seem to make anything worth a crap in this country anymore, the US parts either dont fit, dont hold up, or need refinishing to look decent. AND there expensive, cause they have you over a barrel. You must pay their $50 for these few ounces of metal in each of these 7 or so parts that SOMETIMES have identafieing stamps on them, that cost about $5 to make, or you can chance 10 FRICKING YEARS in prison and loosing your right to have ANY arms at all. Wonderfull isnt it? A nice little extortion setup, highway robbery, what ever you want to call it. That isnt the half of it either, but it's a good simple example. You'll spend many many hours, require a decent bit of knowledge and mechanical skill, and no small amount of money to have one of these rifles. That ticks me off. A lot.
I dont mind the background check at all, it's just commen sence, but some of the laws, like the above one's I mentioned are absolutly silly. No reason for them at all...