there's no clean way to add a crosshair to the painsaw, you would have to stick a crosshair image in the center of your hud, and it will always be drawn, so you get 2 sets of xhairs on your hud on all other weapons. if you're still interested look up one of the alien xhair huds and copy the relevant section to your human hud (and change the image/color to something human looking)