Hunters are very slow, you can kill them with one well place pistol round, run up in front of a hunter, and he should charge at you, jump away to the side to dodge him, turn around, and shoot the orange part on his back, his back will be turned for about 3 seconds or so, long enough. These orange parts are the weak point, they have a few of them, one on they're face whcih is usually blocked (if your sniping them, go for that point) but the orange patch on his back is biggest and easiest to get to with my lil guide. If you hit him directly on the orange, he will die with the single shot.