A thought just occured to me while I was reading Lord of the Rings. The ring can't be used for good, because it's the embodiment of evil will. All those who have come in contact with it are tempted and corrupted. Even when used for something noble, the power of the ring will simply corrupt the wearer to replace one evil with another. The power of the ring is too strong to be resisted, even for Sauron. The ring by itself can do nothing, but it embodies evil will, and as soon as it's wore again, it corrupts the will of the wearer and tempts him to exercise evil power.
So how does this relate to guns you ask? Well, we've discussed many times how guns are just tools. They can't just go shoot people by themselves. Someone has to use it to shoot someone. It's not as if the guns themselves are evil. While in reality we all know that guns are not so powerful that they can corrupt the will of the bearer. Playing devil's advocate here, can't it be argued that guns were created of evil origins, ie. weapons of war/created to kill. Therefore they embody evil, man's desire to kill, wage war upon his fellow man. Since their creation, they've bided their time, waiting for the slightest stir of murderous inclination in a willing host. To be used in a horrifying orgy of violence. So why aren't we sending all of our guns to be annialated in the crack of doom?