Here's the test of the bill:
https://www.murphy.senate.gov/imo/media/doc/bipartisan_safer_communities_act_text.pdf
As far as I can tell most of it is gobbledy-gook, but 2 sections caught my eye
Section 12002 changes the definition of "engaged in the business" as related to being a firearms dealer from ‘‘
with the principal objective of livelihood and profit’’ to ‘‘
to predominantly earn a profit’’. Sounds minor, but it opens the door to severally restricting, dare I say eliminating, private sales. If one chooses to sell a gun for more than what they paid for it then they run the risk of being classified a dealer. Imagine what that would do in MA where dealer sales are constrained by so called "consumer protection laws" in ways private sales are not. I can see it effectively ending private sellers at gun shows, maybe not something we see (much?) around here, but not uncommon in the free world.