I am flushing the buffer of old posts. Here is one I delayed posting because it's just too boring. Well, I'm posting it anyway. Sorry.
xkcd has a provocative comic about cryptography.
I imagine many geeks are moderately in favor of gun control but staunchly opposed to cryptography control. The two issues are very similar.
Having a gun lets you do two basic things: intimidate unarmed people; and resist armed or otherwise violent people. (You can of course just shoot people, but the power of a gun starts working at some remove from that eventuality. Most cops never shoot anyone.) Neither ability is necessary unless something has gone wrong; and both abilities can themselves go wrong in spectacular ways.
I believe in a fundamental human right to self defense, and for both moral and pragmatic reasons I tend to prefer individual rights to the common good where they conflict. So ab initio I pretty much have to oppose gun control unless there is a strong reason to think it's pragmatically the only way to go.
But I also believe gun control is an all-or-nothing proposition in practice: imposing a five-day waiting period before someone can buy a handgun, for example, makes no sense at all to me. Measures that are obviously easily circumvented, like the current U.S. background check, also make no sense. These measures seem squarely targeted at established, law-abiding gun sellers and their law-abiding customers. Effectively preventing criminals from having guns would require serious bookkeeping requirements and a tremendous enforcement effort. Judging by the results in the places where that has been tried (Illinois, the UK) it just doesn't seem worth it.