Genghis Khan's army was composed of only elite warriors; he only allowed expert archers and marksmen, and tough soldiers to join, and they rode nimble horses who could survive in harsh temperatures.
If you are very good at what you do, if you're an excellent what we would call " marksman" or " markswoman, " then they would call you a " sniper" (sniper) or a " sharpshooter."
In this case, Arien says he sends in the skirmishers and the marksmen and the slingers and the archers to go shoot at the Tribali in whatever this terrain is that's keeping Alexander off him.
This time the scout seized the rifle with avidity; nor had Magua, though he watched the movements of the marksman with jealous eyes, any further cause for apprehension.