Guns might deter burglars, but when any irresponsible idiot can get a gun you've got a worse situation. Eg, here are two relevent headlines right from the top of today's front page on CNN, regarding idiots with guns intentionally shooting and killing people.
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Man shoots four and kills two after breaking up with his girlfriend
Man shoots girl for walking a few steps onto his property

FWIW, I'm not entirely anti-gun, I think there are situations and occupations they're certainly warranted. But I don't buy the whole "2nd amendment is my God-given right, guns solve everything and make the world a perfect place" argument either.