The South Dakota-class battleships carried a main battery of nine 16-in (406 mm)/45 caliber Mark 6 guns in three three-gun turrets, identical to the North Carolina-class.
Two of these turrets were placed in a superfiring pair forward; the third turret was mounted aft of the main superstructure.
These guns fired a 2,700 lb (1,200 kg) Mark 8 armor-piercing (AP) shell at a rate of two per minute per gun.
The guns could either use a full propellant charge of 535 lb (243 kg), a reduced charge of 295 lb (134 kg), or a reduced flashless charge of 315 lb (143 kg).
This provided a muzzle velocity of 2,300 feet per second (700 meters per second) for the AP shell with the full propellant charge, while the reduced version provided a correspondingly lower muzzle velocity of 1,800 ft/s (549 m/s).
130 shells were stowed for each gun, which came to a total of 1,170.
The guns in all three turrets could elevate to 45 degrees, but only I and III turrets could depress to −2 degrees; the superfiring II turret was not able to depress.
This enabled a maximum range of 36,900 yards or 18.2 nmi (20.9 mi; 33.7 km) with the Mark 8 projectile.
 The turrets were able to train 150 degrees in both directions from the centerline, which enabled a wide arc of fire.
The guns could be elevated or depressed at a rate of 12 degrees per second, and the turrets could train at 4 degrees per second.
The South Dakota-class battleships carried a main battery of nine 16-in (406 mm)/45 caliber Mark 6 guns in three three-gun turrets, identical to the North Carolina-class. Two of these turrets were placed in a superfiring pair forward; the third turret was mounted aft of the main superstructure. These guns fired a 2,700 lb (1,200 kg) Mark 8 armor-piercing (AP) shell at a rate of two per minute per gun. The guns could either use a full propellant charge of 535 lb (243 kg), a reduced charge of 295 lb (134 kg), or a reduced flashless charge of 315 lb (143 kg). This provided a muzzle velocity of 2,300 feet per second (700 meters per second) for the AP shell with the full propellant charge, while the reduced version provided a correspondingly lower muzzle velocity of 1,800 ft/s (549 m/s). 130 shells were stowed for each gun, which came to a total of 1,170. The guns in all three turrets could elevate to 45 degrees, but only I and III turrets could depress to −2 degrees; the superfiring II turret was not able to depress. This enabled a maximum range of 36,900 yards or 18.2 nmi (20.9 mi; 33.7 km) with the Mark 8 projectile.  The turrets were able to train 150 degrees in both directions from the centerline, which enabled a wide arc of fire. The guns could be elevated or depressed at a rate of 12 degrees per second, and the turrets could train at 4 degrees per second.
South Dakota-class battleship (1939)