Write them a letter and you will get their opinion. It's the only way you'll have any guidance because it entirely depends on how the ATF is feeling that day.

And it has to be a physical letter, they refuse to answer emails.

>>30500346
You'd probably have to completely *sell* the person the machine/materials who would then sell it back once they are finished.

And they'd probably have a problem with it if you were making a business out of aiding the manufacture of firearms without any sort of ffl.

there's a similar thing called a build party. usually it's someone with a milling machine who invites a bunch of people with 80% lowers to come over and finish them on their machine. IIRC it's legal as long as the person who is going to own the lower does the work. in CA (maybe nationwide) if a CNC machine is used, you can run into legal trouble because the programming in the machine counts as a third party working on the lower
tl;dr as long as the person doing the work is the person who's gonna own the gun, you should be OK. As the other anon said you could ask for an ATF opinion letter if you want to be REALLY sure

>>30500749
So I take it having a store that just sells gun parts, ammo and sporting goods but not actual firearms having a router and jig to rent out so a customer could buy an AR upper, parts kits and 80% lower and then rent a router to finish their lower isn't going to fly?

>>30500897
It's probably doable within the bounds of the law but the ATF has never been known for their respect for the law.

>>30500807
This. I've been invited to many build parties in california

>>30501073
Pretty much this.

In principle, you shouldn't have a problem, OP, as none of those components are firearms, but getting ATF approval is in your best interests.

>>30500807
So for a CNC machine, it'd only be legit if every single person programmed their own instructions for the 80 they were finishing?

>>30504598
nope
each person would have to own the CNC and no you can't sell it temporarily

>>30500346
The only way to legally do it would be to buy a bunch of 80% lowers at wholesale and resell them for a profit. You could then inform the customer that you have a shop in back with all of the tools that he would need to complete the lower and he can use them for free. The trick would be that if anybody came in with their own 80% lower, you would have to let them use your equipment as well. If you denied them, then that would be proof that you were charging for the use of your equipment which would put you into legal hot water.

Another way to do it would be to open your shop to the public and put a tip jar out stating that all donations go to maintaining the equipment, i.e. buying drill bits and replacement components.

>>30500897
NO!!! The ATF has decided that you can not rent or loan tools to someone that you believe will use those tools to manufacture a firearm. If you do this, you will get v& and your dog will get shot.

Who makes a 80 percent lower jig with the no no hole?