https://malegislature.gov/Laws/GeneralLaws/PartI/TitleXX/Cha...
I am a Mass resident and know not to mess with Mass gun laws - they carry a minimum of 2 1/2 years in jail.
Total coincidence - MA has the lowest gun death rate at <1/3 the national average and <1/6 some of the most dangerous states: https://en.wikipedia.org/wiki/Firearm_death_rates_in_the_Uni...
Boston is your big city, right? It had 56 people murdered in 2018. Here are their pictures. https://www.universalhub.com/2018/boston-murders-2018
As near as I can tell from the available pictures, the victims are largely or entirely black. They make up 23% of the city, according to wikipedia, or 159,754 people. So that is about 35 black victims per 100,000 black residents.
In 2018, Chicago is about 40 black victims per 100,000 black residents.
This is comparable to black victim rates elsewhere. I don't think that your gun rates are helping so much as the fact that you are a mostly white state without many urban centers.
Seeing the faces of the victims really hammers home the reality of murder in the United States: something that's much worse for black men (and the black community) than it is for everyone else.
And yet Massachusetts' murder rate of 3.2/100k/yr is right about the median for the US. Who ever would have thought? (Granted, the suicide rate of 8.8/100k/yr is pretty impressive, and some of that might be assignable to their gun control efforts)
Murder is when one human wants to kill another and that's not hard, humans are as dedicated as they are fragile.
What availability of guns influences most are homicides. Where you don't necessarily want to kill another human but you want their stuff or you want to teach them a lesson, also accidental deaths and I think suicides (probably quickness and decisiveness draws people).
Do background checks help prevent suicides or accidents?
On the other hand, waiting periods, permit to purchase, etc., may be more helpful in preventing suicides (or minimizing fatal suicide attempts).
What were the statistics and trends in Massachusetts before the laws were in force?
It's important to look at the intent and effect of proposed (and on-the-books) legislation, and at the context of statistics.
There is a good discussion of various factors (duration of suicide crises, availability of means, opportunity to abort the attempt or be rescued, and the lethality of the mechanism).
"Nine out of ten people who attempt suicide and survive will not go on to die by suicide at a later date."
"A number of studies have indicated that when lethal means are made less available or less deadly, suicide rates by that method decline, and frequently suicide rates overall decline. This has been demonstrated in a number of areas: bridge barriers, detoxification of domestic gas, pesticides, medication packaging, and others."
https://www.hsph.harvard.edu/means-matter/means-matter/saves...