Two thoughts
First: Weapons are a tool of humans, I don't have claws or particularily sharp teeth. If I want meat, (moose, deer) I am going to have to use some form of weapon (gun, bow, ect) Of course there will be the crazy vegitarians out there that believe killing is wrong, that we should be in harmony with animals. Well, they are blind to the real world, animals kill each other, right now there is a million animals killing a million other animals, its the way it works. Life cannot be sustained without death, it is an intrinsic balance. I think it is far better to have respect for your prey then to have no prey.
Second: Seriously ask yourself, why is it immoral to kill people? Don't get me wrong, I would not kill another person, but I think it is important, (mostly for non-religious people, because religious people have an easy answer) but for the atheisists out there, why is it wrong to kill another person? If we just went around killing the weak, our population would be under control and the human race would be stronger as a whole. So where is the inherant evil in killing another man? (A question I had to think about in a class I took, Evil in World Religions)