I have a gun design I want to make and sell, but do not have the funds to get all the permits/licenses needed to do it all the way. I know it is legal to manufacture and sell unfinished receivers of a firearm without a manufacture FFL license, do anyone know where can i find laws specific to that so I can read them and determine whether I want to do is legal or not.

I have a semiautomatic handgun design in mind, I know its legal to manufacture firearms for personal uses, that is not to sell it or transfer possession of it to anyone else. but if I was to sell it, would it be legal to sell a gun with an incomplete receiver where the end-user (customer) has to finish it himself to make the firearm functional? and how incomplete does a receiver have to be for it not to be considered a firearm? such an AK receiver blank, as a sheet of steel its not a firearm. it requires someone to press it and rivet it before it becomes a "receiver".

-thanks
my idea is for a one piece, cast pot metal receiver. everything else of the gun is using common parts from other firearms. for example, it uses an SKS bolt cover, AK trigger group, Hi Point 9mm magazine spring (fixed 10 rd magazine), etc. even the barrel was designed to be easy to find.
I just need to know exactly how unfinished a receiver needs to be so its not considered a "gun".
I plan on design something with a 3d printer, make a plaster mold (2) of that printed part, and use each half of the mold combined together to create one cast metal receiver, complete with all the holes and shapes, all the end user has to do is file, sand, and maybe re-drill some of the holes. requires no special tools at all, nothing you can’t get for 20 bucks at walmart. and I figure I’d ship the cast receiver, complete with plaster mold in one of those USPS flat rate boxes. the plaster serves as packaging material too.

so when you open this box all you see a block of white plaster and a card with inst

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