Designated marksman

The designated marksman (DM) or squad designated marksman (SDM) is a military marksman role in an infantry squad. The term sniper was used in Soviet doctrine although the soldiers using the Dragunov SVD were the first to use a specifically designed designated marksman's rifle. The analogous role in the Israeli army is sharpshooter.

The DM's role is to supply rapid accurate fire on enemy targets at ranges up to a maximum of 1,100 yards (1,000 m) with a rifle capable of semi-automatic fire called a designated marksman rifle equipped with a telescopic sight. Like snipers, DMs are trained in quick and precise shooting, but unlike the more specialized "true" sniper, they are an intrinsic part of an infantry fireteam and intended to lay down accurate rapid fire at valuable targets as needed, thus extending the reach of the fireteam.

The growth of the DM rifle can be attributed to two main influences; the near-universal adoption of intermediate cartridges, such as 5.56×45mm and 5.45x39mm, for standard service rifles, and the increasing specialization over the last 15 years of Western sniper rifles and their employment of more powerful rounds, such as .300 Winchester Magnum and .338 Lapua. These two influences have left a gap in the firepower of the rifle platoon that a more accurate optic-equipped service rifle derivative can usefully fulfill, especially in theaters such as Afghanistan where the shortcomings of standard 5.56mm service rifles at ranges over 300 m became apparent.

...
Wikipedia