Gun Control & RKBA

yet still imply that firearms aren't heavily regulated?!?!

In one sentence you declare that private gun sales are "completely unregulated," and then in the very next sentence admit that a "seller (can)not knowingly sell to a felon or other restricted person." "Completely unregulated" does not mean what you think it means.

I would also note that private individuals do not have access to the NICS database to conduct background checks of prospective purchasers, and although such access is supported by gun rights proponents, it is largely opposed by gun control advocates because they believe it would hurt their case for more stringent background check legislation. If you and your ilk believe the perfect the enemy of the good, there's not much anyone can do.

Again, because you believe that the existing regulations are insufficient does not mean that firearms are not heavily regulated.

As to regulations concerning "features, methods or other aspects of making a gun," you apparently have not read the National Firearms Act of 1934, the Undetectable Firearms Act, the Firearm Owners Protection Act, and the host of other federal, state and local laws and accompanying regulations.

https://en.wikipedia.org/wiki/Gun_law_in_the_United_States