A unit trained in marksmanship, who can shoot relatively farther than the average unit due to training and his trusty M-40. He is good if teamed with a high observation soldier for example a ranger, as a ranger can spot an enemy and let the sniper shoot him. A sniper on his own isn't any better than a normal marine if he has low observation.
He is the equivalent of a sniper in MnB2.
The sniper was possibly the most terrifying thing in the jungle. He is well camouflaged, far away, and you will not know when he hits you. Snipers were used to disrupt enemy movement, to act as the "eyes and ears" of the unit they were attached to, and on rare occasions to eliminate specific targets. They also provided pin point fire support and the long range killings lowered enemy morale.