Allie I know how you feel, there is so much bullying gong on in the schools and it seems like nothing is being done about it. You can understand kids wanting to take weapons to protect themselves and how that makes the cycle worse.
Motherly instinct sees you wanting to go and remove parts of the other kids anatomy but you have to be restrained as it doesnt just reflect on your son, it reflects on you too.
My youngest daughter came home really upset recently when a girls mother verbally attacked her in front of a group of kids for a situation that hadnt happened, just some kid stirring the pot and things got out of hand. When the truth finally surfaced, the girl apologised but the mother didnt. You can imagine my thoughts on this woman and my wanting to go slam her thick head into a brick wall, but I had to draw the line. Thing is, I wont forget and the way things are in this town, one day she will be needing something from me or one of my contempoarires and I assure you she wont be getting anything.
I wish I could offer a solution but all I can think of is to get your son to learn some form of martial arts, even pacifists do such things, he might even end up enjoying it. Its amazing what it does to your self esteem and of course helps you in such situations. I learnt it after my violent previous marriage broke up and ended up teaching for years and it has helped me a lot. No one can mess with me now!