My step-son had a bully attacking him for years. He asked me what to do, I advised him to 'Pick his Battles Wisely'. He waited till the last day of school one year and when the bully came over he beat the snot out of him.
He was taken to the school office and the administrator, who told him not to do any violence again, that he was surprised at him (having be a quiet boy for years). Yet there was no punishment, for it was well know that the bully had been at it with many other kids.
The Bully never came back, because he could never figure out when my stepson would explode again. My stepson has since graduated from Valley Forge Military college (yes, that Valley Forge) and is now a Staff Sargent in the Airforce.
Yes, he learned to choose his battles wisely.