The Raufoss Mk 211 is a .50 BMG (12.7×99mm NATO) multi-purpose anti-materiel high-explosive incendiary/armor-piercing ammunition projectile produced by Nammo under the model name NM140 MP.[1] It is commonly referred to as multipurpose or Raufoss, meaning red waterfall in Norwegian. This refers to Nammo’s precursor company Raufoss Ammunisjonsfabrikker, an ammunition manufacturer established 1896 in Raufoss, Norway. The “Mk 211” name comes from the nomenclature Mk 211 Mod 0 used by the U.S. military for this round.The multipurpose concept developed by Raufoss is unique in that, instead of using a mechanical fuse, it uses a pyrotechnical ignition train to ensure proper deflagration (not detonation) of the explosive and incendiary components.
The multipurpose name is based on an armor-piercing tungsten core, a slow explosive, and an incendiary component, thus making it capable of penetrating lightly armored targets and causing damage to personnel inside the target after penetration. It is a suitable round for engaging helicopters, aircraft and lightly armored vehicles, as well as unarmored vehicles, and it is capable of igniting jet fuel. The Mk 211 has about the same destructive power as a standard 20mm round against such targets and can penetrate 11 mm of RHA at 45° from a range of 1000 meters. The slower-burning deflagration action results in a characteristic fragmentation pattern with large pieces dispersed in a 30-degree cone.
The Mk 211 is a very popular .50 caliber sniper round used in the Barrett M82 rifle and other .50 BMG rifles.[5] It is also often used in heavy machine guns such as the M2 Browning. Due to its popularity, several U.S. arms manufacturers produce the round under license from NAMMO Raufoss AS. However, due to the complex structure of the projectile and consequently high costs (ca US$75 per round), the popularity is restricted to special mission profiles.The Mk 211/NM140 is graded into two accuracy classes: Class A is match grade ammunition, while Class B is ordinary linked ammunition for machine gun use. Under the international (or Norwegian) NM nomenclature, revisions are indicated by a trailing “Fn”, with “F3” being the current revision as of 2020. There is also a tracer variant, the Mk 30/NM160 in Norwegian service, used in the Browning heavy machine gun. The “DT” (IR tracer) variant called NM 263 is not used by the US