a) guns are used more for harm than good. if your hobby is hitting the target range, sorry bro, find a new one.
b) we can't effectively control who gets guns and who doesn't. in an ideal world, sure, only smart people who were responsible would be given access to them, but we don't live in that world. we live in a world where we have to either give something to everybody or nobody.
in the scenario of giving everyone a gun
pros
situations were you required a gun to protect yourself
cons
accidental death
crime
escalation
in the scenario of giving nobody a gun
pros
less accidental death
less deadly crime
less disputes ending in death as opposed to a punch in the face
cons
situations where you required a gun to protect yourself
but even that con = so what, because if you really feel like you need a gun to protect yourself, you should either move the fuck out of the shithole you live in, learn not to walk the streets at 4am, or not engage people in violent ways. after all, turning an running is always your best option. the only people who rationalize gun use as a deterrent to crime are people who are violent themselves and need to have an edge. i.e, not someone i want with a gun in the first place (point to escalation).
so from a logical perspective, there is realistically no scenario where you can say that having a gun is better than not having a gun.
and if your argument is "well other weapons are used for harm too". sure there are. a toothpick or paperclip could be used for harm. the difference is that it's not as easy to go on a murdering rampage with such tools. likewise, when the amendment was implemented, guns weren't used as such violent public killing machines. but nowadays, give someone a couple of handguns though and you have 15 dead people in about 5 seconds with no possible way to defend themselves. you say you have the right to bear arms, i say i have the right to walk the streets knowing there aren't 8 people around me who could kill me with the flinch of their pointer finger.
if you want the right to bear crossbows, im all for it. you might squeeze off a nice headshot, but then you're stuck reloading, all the while 4 people tackle you and pound your skull in. and you're safe in the zombie apocalypse since theyre all so slow moving the reload time wont hold you back much. look at daryl dixon from the walking dead. he's doing just fine. but these 1 man killing sprees that you just cannot defend against need to stop, and giving other people more guns doesn't lead to less casualties. no guns and everybody settling their rage with fists or chains, road rage style will be the worst thing we have to worry about, and that's enough of a deterrent in itself because if you want to take the cowards way out and turn your own fists or chain on yourself, you're going to take a serious hurting before you do yourself in.