Simply not true; people who buy cocaine and heroin by the ton have no trouble having the supplier toss in some guns.   A fully auto AK is available in most of the Third World for about $100; they pour into the US as do all sorts of Third World copies of brand-name handguns.    A US legal semi-auto AK platform weapon starts at about $800 and goes up, way up, from there.   A decent AR platform starts at about $1000 and goes up, way up, from there.   A decent US legal, gun shop bought handgun starts at about $500 and goes up, way up, from there.   These guys are trading smuggled and stolen guns for bags of dope or use of women mostly; there is no law you could pass that would stop that and most of it is illegal anyway.   A Helluva lot more police presence in some neighborhoods would help a lot though.