The M16 family were gas-operated, selective-fire (full automatic or semiautomatic), self-loading rifles feeding from detachable 20- or 30-round box magazines. A bipod can be fitted, as can a bayonet. A typical rifle weighed just over 3kg (6.61b) and measured 990 mm (36.6 in) in length. The flip aperture rear sight of the rifles was contained between flanges (for protection) on the fixed carrying device located on the receiver above the pistol-grip trigger mechanism. This carrying handle gave the M16 some of its characteristic outline. The design of the weapon incorporated the 'in-line recoil' feature that had been known about for some years before. This meant that the recoil from firing drove the weapon in a straight line along the line of sight, so that the tendency for the rifle to move off the point of aim was considerably reduced. It also tended to limit the climbing effect when firing on automatic or bursts. The flash suppressor, which is fixed, can be used to fire standard rifle grenades. The compact nature of the M16 made it an easy weapon to carry into combat.