My assumption is that the insurgents want to engage as close-in as possible to mitigate our units support from Arty or Air assets. Plus, the closer you are the less the advantage goes to the better trained marksmen. At least in the U.S., our law enforcement gunfight survival stats sky rocket the farther the engagement distance. A lucky shot from a rusty .38 will kill you just as dead as one from well maintained Sig. They are probably trying to get in close for short engagements and then breaking off before any reaction forces can intervene.