The most significant acts restricting arms federally are the NFA (1934) which was a (at the time onerous) tax because they weren't sure they had constitutional

The most significant acts restricting arms federally are the NFA (1934) which was a (at the time onerous) tax because they weren't sure they had constitutional power for many other methods of regulation. The other was the GCA passed in 1968. After the passing of the NFA was the beginning of many modern era challenges such as US v.no legal counsel of dead guy (Miller). Unsurprisingly the undefended dead guy with no counsel lost setting a long precedent and the rest of NFA is history.