what do the speed shops do to the car than allows it to do something it could not do before the shop's added processes?
making it shineyer or faster or brake better are not functions the car could not do before. it could already go fast, be shiney, and brake
you illustrate a lack of understanding about what constitutes being a manufacturer. just as many have the same misunderstanding as presented in the OP about why a gunsmith is treated as a manufacturer
How about air suspension or hydraulics where the car can lift itself? Couldn't do that before..
What about adding a key fob car starter? Couldn't start it from in your house before..
What about adding a dvd tv entertainment system to the car? Gps, wifi hotspot.. Couldn't do any of that before..
You can make your exhaust spit flames with sparkplugs..
Legal gunsmiths are the last people on earth you should be concerned about making weapons automatic..
That would be like asking the magistrate how to bribe the judge.. Or asking the TSA how to get your coke on the plane..
Only complete morons would seek out a professional gunsmith to illegally modify their guns..
I don't even understand your arguments about "doing something it couldn't do before".. Like what? What is the gun going to do? Your taxes?
It's going to shoot bullets, but just better.. So what?
Or you could just buy a better gun that shoots bullets better.. You can but like $5k ARs and its plenty good for anything.. So why not be able to slowly build a $1k AR into a $5k AR?
Converting to FULLY automatic? Gunsmiths don't do that.. They work on fully automatics for the gov and whatnot but the people that buy fully automatic guns buy them full auto in the first place..
Only the gov buys fully automatics, I doubt they are fussing around converting any, they will commision them the way they want them in the first place..
No citizens buy fully automatics, they can only trade old collector ones, not buy new, nor convert to full auto..
I'm pretty sure the act of converting to full auto is "manufacturing" by law and has been for a long time.. Gunsmiths don't convert guns to full auto so they aren't manufacturers.. It's just not something they would do that wouldn't be an extreme regulatory specialty for obscure reasons..
Anyway.. Doing a trigger job on a gun is not manufacturing, you just make it smoother.. Changing the grips or upgrading to lighter stronger higher precision parts just make the gun operate better.. Some people have a thing for their stuff being above average...