Designated Marksman. military marksman role in a U.S. infantry
squad. The DM's role is to supply rapid accurate fire on
enemy targets at ranges up to 870 yds with a highly-accurate
semi-automatic rifle equipped with a telescopic sight. Like snipers, DMs are trained in quick and precise shooting, but unlike the more specialised "true" sniper, they are also intended to lay down accurate rapid fire.