Anti-tank rifles were introduced in some armies before the Second World War to provide infantry with a stand-off weapon when confronted with a tank assault. The intention was to preserve the morale of the infantry by providing a weapon that could actually defeat a tank. Anti-tank rifles were developed in several countries during the 1930s. By the beginning of WW2, anti-tank rifle teams could knock out most tanks from a distance of about 500 m, and do so with a weapon that was man-portable and easily concealed. Although the AT rifle performance was negated by the increased armor of medium and heavy tanks by 1942, they remained viable against lighter-armored and unarmored vehicles, and against field fortification embrasures.