Ok, um, so I'm in the know here (see user name/uid). Also, I'm a Texan, so that possibly qualifies me by birth...
The weapons you are describing are military derivative firearms and by all rights, SHOULD be banned IMO. We, as a nation, have proven ourselves incapable of properly storing our firearms, incompetent at assessing who should have a firearm, and generally promoting the glorification of firearms use via the media, games, and certain aspects of our culture.
At the same time, we have tried to claim that the right to own firearms does not come with any responsibility. If your kid leaves his toys out, after several warnings, you, as a parent, would be taking a reasonable stance to put the toys away for him. The child (in this badly crafted analogy) has not demonstrated the responsibility that comes along with the right to those toys. Same for those of us in the gun culture. We have failed at our responsibility to safely possess firearms. We do not deserve them now.
You said something that I'd like to point out to be overdramatic in the least, and possibly flat-out manipulative; "now the vast majority of us - who will never use them irresponsibly - need to suffer". Can you please tell me how much you will suffer? If we combine the total suffering from all the people in the state who will lose their guns, do you believe that it is greater than the suffering felt by any combination of the parents of the Sandy Hook victims? If you want to bring suffering into this discussion, let's keep that perspective in mind.