There are other 80% complete frames available and have been for a long time. The most popular are the AR-15 and 1911. It seems like the line is fairly well established. There are other issues like felons and other people who can't have a gun using this to get around the background checks that can lead to raids and questions about the makers of these billets but in general if you can own a gun you're perfectly safe to buy an 80% billet and machine it out yourself.
Are you talking about the CNC shop that was trying to act like just starting or touching the machine was enough to count as their customers manufacturing the lower instead of the company? That's a whole other issue with just what does it mean for a person to have manufactured the weapon and I'm pretty comfortable saying that company was well on the wrong side of that line.
For most 80%s they're pretty clearly not a gun because there's absolutely no way to use this [1] without modification and assemble it into a gun. This basic design has been around for a looong time.
Are you talking about the CNC shop that was trying to act like just starting or touching the machine was enough to count as their customers manufacturing the lower instead of the company? That's a whole other issue with just what does it mean for a person to have manufactured the weapon and I'm pretty comfortable saying that company was well on the wrong side of that line.
For most 80%s they're pretty clearly not a gun because there's absolutely no way to use this [1] without modification and assemble it into a gun. This basic design has been around for a looong time.
[1] https://cdn.shopify.com/s/files/1/0218/5770/products/DSC0545...
Edit: found a pretty in depth Q&A with the ATF about 80% lowers that defines and clears up a lot of things like exactly what would make an incomplete lower count as a firearm: https://www.ammoland.com/2014/11/atf-answers-questions-on-80...