Joseph Greenlee.

Since the earliest colonial days, Americans have been busily manufacturing and repairing arms. In the colonies, the ability to defend one’s home and community, hunt, fight wars, and ultimately win American independence depended largely on the ability to produce arms. For the newly independent nation, arms production was critical to repel invasions and insurrections, and eventually, to western expansion. The skill was always valued and in demand, and many Americans made their own arms rather than depend on others. Americans continued producing their own arms in the nineteenth and twentieth centuries, leading to some of the greatest technological breakthroughs in the history of firearms and ammunition. The freedom to build personal arms enabled innovations that allowed Americans to better defend themselves and their country than ever before. Meanwhile, restrictions on self-made arms have been rare throughout American history. All restrictions on arms built for personal use have emerged within the last decade, and from only a few states. While still uncommon, legislatures are increasingly targeting homemade arms due to the growing popularity of unfinished receivers and 3D-printed firearms.

[ … ]

Heller established several principles that support the right to build arms for personal use. First, under Heller, any analysis must start with the Second Amendment’s text, which protects the right to keep and bear arms and provides no reason to believe that people must buy the arms they wish to keep and bear. Second, Heller held that the Second Amendment protects the types of weapons that are commonly possessed for lawful purposes, regardless of how those arms are acquired. Third, Heller suggested, as lower courts have recognized, that the Second Amendment also protects the right to acquire arms, which includes building them personally. Fourth, history and tradition—which is used to inform the Amendment’s text under Heller—reveals that Americans have long enjoyed and depended on the unregulated right to build arms since the colonial days. In sum, the right to build arms for personal use is a right protected by the Second Amendment.

There’s a lot between the introduction and the conclusion statements and you’re welcome to read it at your leisure.  The founders would be appalled at the notion that the federal government has the right to regulate the making of arms.  They fought and some perished for the sake of living as free men, and that included the right to lack of interference in things that occupied them daily.

They would be even more appalled at the notion that unaccountable bureaucracies would have the authority to regulate such matters.  They said something about that, yes?  “He has erected a multitude of New Offices, and sent hither swarms of Officers to harrass our people, and eat out their substance.”

They only have that authority based on police powers, the power of confiscation, and the power of taxation, also all things the founder opposed for the federal authority, and things they do not because they have that right, but because no one has stopped them.