The big problem with gun laws is twofold IMO:
1-it prevents the law abiding people, who might otherwise have no defense against an attacker from not being slaughtered by those determined to do so.
And 2-hardcore scumbags, terrorist jihadis, career criminals? gun regulations aren't going to make a difference, because those hellbent on violence of that nature, school shooters etc. they don't give a fuck about a few regulations, when they want the guns for purposes of indiscriminate slaughter. Thus such regulations actively serve to enrich the proportion of armed criminal thuggish elements to those who are law abiding, nonviolent and forced to remain unarmed but for what they have the means to arm themselves with (E.g things like coilguns, ECT cannons, railguns, nasty little contraptions built from microwave emitters and waveguides and pulsed power sources etc.)
So the law abiding who want weapons to defend themselves find themselves restricted, whilst the thugs and the terrorists aren't taking the least bit of notice in the first place.