6"/53 caliber gun 6"/53 caliber gun The 6"/53 caliber gun (spoken "six-inch-fifty-three-caliber") formed the main battery of some United States Navy light cruisers and three US submarines built during the 1920s. United States naval gun terminology indicates the gun fired a projectile 6 inches (15 cm) in diameter, and the barrel was 53 calibers long (barrel length is 6 inch x 53 = 318 inches or 8 meters.) The gun with side swing Welin breech block and Smith-Asbury mechanism weighed about 10 tonnes and used a silk bag containing 44-pounds (20 kg) of smokeless powder to give a 105-pound (47.6 kg) projectile a
Human hair color years old, 74% had some grey hair, covering an average of 27% of their head, and approximately 1 in 10 people had no gray hairs even after the age of 60. Children born with some hair colors may find it gradually darkens as they grow. Many blond, light brown, or red haired infants experience this. This is caused by genes being turned off and on during early childhood and puberty. Changes in hair color typically occur naturally as people age, eventually turning the hair gray and then white. This is called achromotrichia. Achromotrichia normally begins in the early to mid-twenties