right hand from the pistol grip, which is ergonomically sub-optimal. Some AK-type rifles also have a more traditional selector lever on the left side of the receiver, just above the pistol grip. This lever is operated by the shooter's right thumb and has three settings: safe (forward), full-auto (center), and semi-auto (backward). Sights The AK-47 uses a notched rear tangent iron sight calibrated in increments from . The front sight is a post adjustable for elevation in the field. Horizontal adjustment requires a special drift tool and is done by the armory before issue or if the need arises by an armorer after issue. The sight line elements are approximately over the bore axis. The "point-blank range" battle zero setting "П" standing for постоянная (constant) on the 7.62×39mm AK-47 rear tangent sight element corresponds to a zero. These settings mirror the Mosin–Nagant and SKS rifles, which the AK-47 replaced. For the AK-47 combined with service cartridges, the 300 m battle zero setting limits the apparent "bullet rise" within approximately relative to the line of sight. Soldiers are instructed to fire at any target within this range by simply placing the sights on the center of mass (the belt buckle, according to Russian and former Soviet doctrine) of the enemy target. Any errors in range estimation are tactically irrelevant, as a well-aimed shot will hit the torso of the enemy soldier. Some AK-type rifles have a front sight with a flip-up luminous dot that is calibrated at , for improved night fighting. Furniture The AK-47 was originally equipped with a buttstock, handguard and an upper heat guard made from solid wood. With the introduction of the Type 3 receiver the buttstock, lower handguard and upper heatguard were manufactured from birch plywood laminates. Such engineered woods are stronger and resist warping better than the conventional one-piece patterns, do not require lengthy maturing, and are cheaper. The wooden furniture was finished with the Russian amber shellac finishing process. AKS and AKMS models featured a downward-folding metal butt-stock similar to that of the German MP40 submachine-gun, for use in the restricted space in the BMP infantry combat vehicle, as well as by paratroops. All 100 series AKs use plastic furniture with side-folding stocks. Magazines The standard magazine capacity is 30 rounds. There are also 10, 20, and 40-round box magazines, as well as 75-round drum magazines. The AK-47's standard 30-round magazines have a pronounced