There is not really a line to be drawn with gun ownership, in terms of personal defense.
If a criminal plans a home invasion, they will plan it with the best means at their disposal. If they can get a hold of fully automatic weapons, why do the families being invaded have to suffer because they did not have equivalent means, or any means at all to defend themselves? The cops ain't gonna arrive soon enough to save the day, that's for sure.
Someone threatens me or my family (if I had a family), it's the grave (or at the very best, an extremely extended--to mean permanent-- stay in ICU/CCU) for that individual, plain and simple.
And yeah, I do want the best. If it's good enough for criminals to invade my home, or looters to take to the streets, then it's good enough for me to defend my home or my street. The AK-47 has the advantage of being an all around good weapon. Tough to kill, and fires a larger caliber round in comparison to the AR. The AR has the advantages of range and accuracy, whilst not being quite as robust as the AR.
Weapons being registered is just another act of big government intervention. Big government insinuating their control over peoples' lives. If I had to kill someone because they invaded my home or threatened me and my family, sorry, but I did it with my weapon that I own, and I should not have to lose my weapon to criminal investigations because I defended my life (or my loved ones' lives) with it. "Hey, there's the a**hat lying dead on the ground because he was stupid enough to threaten me or my friends or my loved ones. Take him away, not the means to defend myself in the future."
Yes, I do believe in screening prior to ownership of a firearm. But, it's just as easy to be able to acquire a weapon now, thanks to the internet. There used to be a 14 day wait on handguns. One can walk into a pawn shop and buy the pistol of their choice, and walk out with it same day because the background check can be done via internet. But, if the person passed, well, they get the firearm. If it shows up that a potential buyer has a felony conviction, or has mental issues, then hell no that weapon's not going to be sold to them, not unless the seller wants to end up with jail time as well.
I also believe in licensing, just like drivers' licenses. Same rules apply. If you are a convicted felon, or have a history of mental questionability, then you are not to be able to obtain a license for a firearm. Ideally a license means that I am clean to carry a weapon, that I am a responsible owner of a weapon(s), and that I know how to use it properly. Use the weapon illegally (robbery, home invasion, murder), then obviously you lose the license, as well as your ability to obtain one in the future, to say nothing of legally obtaining firearms. Unlike vehicular licenses, firearms licenses should be a one time thing. You lose it, there is no chance of getting it back, if you used your firearm in a criminal act.
Then again, all of the above is academic. Why would a potential criminal go about legal means to obtain the tools of their trade? The less of a paper trail they leave, the less that can be used to convict them, save for the fact that they would have charges of illegally owning/using a firearm without license.
I'm not scared of guns. Guns don't fire themselves. I'm scared of the people that can use them, and that's why I prefer to be able to defend myself under equivalent circumstances. Better to be on the negotiating end of a gun, rather than the business end.
Besides, there's vehicular homicide committed a lot of times too...does that mean we have to ban vehicles now?
Look. I get it. Some folks are afraid of guns. Because of that fear, they feel that no one else should be brave enough to own one. Only the military and law enforcement should have guns, which in turn means that only criminals would have guns. Fine and dandy except that the military and law enforcement cannot arrive in time to save the day before all the damage has been done. To be able to defend one's self should be an undeniable right, and that's why "the right for civilians to keep and bear arms shall not be questioned", although, sadly, it is now the case.