what makes you think that your attackers won't use darkness, movement, cover? why will you have the time to do nothing but hide and watch around you 360 degrees, 24-7? Why would you let yourself be in open country, in daylight? You have no ground to hold, no help, no time schedule. So why fire at longer ranges? Even if you hit, you'll not hit others, if they start dodging on the way to cover. They were unaware of your presence (or they'd not be holding still, in the open, in daylight). If those conditions (along with no wind, no mirage, spotter shots and all that bs) are in position and it's only 1-2 guys, why be so scared of them? How will you know that they are not just scouts, for 100 more enemies that you can't detect? So shooting them just brings the 100 down on your head! you wont have uncle sugar to come evac you, call in air strikes, etc. So why are you firing at long range, eh?