Such a load of Bull
From the AP: "You just pull a trigger and 20 or 30 rounds come in a second and in those 20 rounds you're sure to hit your intended target and some innocent bystanders, totally unlike a firearm that is just one bullet every time you pull the trigger," Miami Police spokesman Willie Moreno said.
Well if they can shoot "20 or 30 rounds in one second" they have to be full auto, so where are they getting them? As of 1986 you could no longer buy full auto weapoons unless your are law enforcement or military, so if in fact they are "Fully Automatic" weapons they have been smuggled in the US, & that is already illegal.
And well ok in some cities homicides are down & some cities it's up, so it will balance out about the same, & not all homicides are gun homicides.