" ''Every guy you kill, there's always going to be someone else," said Corporal Glen Handy, 26, of Las Vegas. Pulling back to observation posts can be ''frustrating for the Marines" said Captain Christopher Bronzi, 31, of Poughquag, N.Y., commander of the Second Battalion's Golf Company. ''You wonder what they are doing out there," he said, referring to insurgents. ''We'd be doing more good if we weren't here. We can send soccer balls from America," said Corporal Nat Canaga, 18, from Colorado, who was wounded by a grenade while on foot patrol." "