Quote:
The impetus for the National Firearms Act of 1934 was the gangland crime of the Prohibition era, such as the St. Valentine’s Day Massacre of 1929, and the attempted assassination of President Franklin D. Roosevelt in 1933.[1][2]:824[3][4] Like the current National Firearms Act (NFA), the 1934 Act required NFA firearms to be registered and taxed. The $200 tax was quite prohibitive at the time (equivalent to $3,526 in 2015). With a few exceptions, the tax amount is unchanged.[3][4]
Originally, pistols and revolvers were to be regulated as strictly as machine guns; towards that end, cutting down a rifle or shotgun to circumvent the handgun restrictions by making a concealable weapon was taxed as strictly as a machine gun.[5]
since (effectively) banning handguns is unconstitutional, you have the nfa, which its weird artifacts like making it illegal to put stocks on pistols, have rifles with barrels shorter than 16" (even if the overall length is beyond the legal limit), and regulation on suppressors because you might (as hollywood teaches) silently assassinate someone. my 9mm suppressor is around 128 dba, which is day and night difference from unsuppressed (i was shooting suppressed, and moved on to an unsuppressed 9mm but forgot to put my ear plug in one ear--ouch. my ear was ringing for hours after just one shot). However, it is still pretty loud and your ears will ring if you shoot a couple of mags with zero hearing protection. Fun as hell though, especially on steel 
