I showed that sprint clip to my supervisor, a former colour sergeant in the Royal Marines commandos. his answer?
"If the drill instructor saw do you that in training he'd knock you up and down the drill square harder than a yank drill sergeant could scream at you for such shoody gun discipline. the only time a rifle should be aimed in the air one handed is if its being reloaded and that's only if its the most comfortable way for you"
it makes the player look 'macho' and 'cool' but in reality makes the 'elite' soldiers ghost recon portrays look very unprofessional and sloppy