You can accurately shoot your SOCOM or Fa-Mas across entire rooms. Equip either Night Vision Goggles or Thermal Goggles, then look at the targeted guard in first person view mode. The view will be broken up by a y-axis line and a x-axis line, forming crosshairs not unlike the those from the PSG-1. Line the intersection of the crosshairs on the guard's body, like you would if you were shooting the PSG-1. Release the first person view mode, the shoot the guard.