line and the triarii in the third line. While the triarii were still armed with hastae, the hastati and the principes were rearmed with short swords and heavy javelins. Each soldier from the hastati and principes lines carried two javelins. This heavy javelin, known as a pilum (plural pila), was about two metres long overall, consisting of an iron shank, about 7 mm in diameter and 60 cm long, with pyramidal head, secured to a wooden shaft. The iron shank was either socketed or, more usually, widened to a flat tang. A pilum usually weighed between , with the versions produced during the empire being somewhat lighter. Pictorial evidence suggests that some versions of the weapon were weighted with a lead ball at the base of the shank in order to increase penetrative power, but no archaeological specimens have been found. Recent experiments have shown pila to have a range of about 30 metres, although the effective range is only 15 to 20 metres. Pila were sometimes referred to as "javelins", but the archaic term for the javelin was "verutum". From the third century BC, the Roman legion added a skirmisher type of soldier to its tactical formation. The velites were light infantry armed with short swords (the gladius or pugio), small round shields, and several small javelins. These javelins were called "veruta" (singular verutum). The velites typically drew near the enemy, hurled javelins against their formation, and then retreated behind the legion's heavier infantry. The velites were considered highly effective in turning back war elephants, on account of discharging a hail of javelins at some range and not presenting a "block" that could be trampled on or otherwise smashed – unlike the close-order infantry behind them. At the Battle of Zama in 202 BC, the javelin-throwing velites proved their worth and were no doubt critical in helping to herd Hannibal's war elephants through the formation to be slaughtered. The velites would slowly have been either disbanded or re-equipped as more-heavily armed legionaries from the time when Gaius Marius and other Roman generals reorganised the army in the late second and early first centuries BC. Their role would most likely have been taken by irregular auxiliary troops as the republic expanded overseas. The verutum was a cheaper missile weapon than the pilum. The verutum was a short-range weapon, with a simply made head of soft iron. Legionaries of the late