How private companies recruit former child soldiers for military operations in Iraq, Afghanistan and elsewhere. From opportunistic guns for hire on the fringe of domestic conflicts to a global force operating within a multibillion-dollar industry - the private military sector seems to be flourishing. As armies and war increasingly become 'outsourced', private military companies have taken on a wider increasing range of responsibilities, from security and intelligence analysis to training and combat roles. "The private military industry is a part of how the countries fight wars today ... The US government doesn't track the number of contractors used in places like Iraq or Afghanistan. We know it's a lot, we don't know exactly how many," says Sean McFate, a professor at Georgetown University who used to work for a private military company.