Parade Field

Moored at her museum berthing in Camden, New Jersey. The reader may notice that Turret 2 (second from the bow) has all three of its guns - the turrets were designed so that guns could be swapped out as the rifled liner within each barrel wore out. Another gun tube would be inserted in place of the worn out weapon and used until it was also worn out. Each shot fired through a rifle, especially of this size, removed a small amount of material from the rifling within the barrel as a result of the friction, gasses, and explosive energies produced by the shell hurtling through the tube with propellant forcing it forward (this usually included expanding a ring around the base of the projectile that would engage the rifling rings and impart spin on the projectile - for long range accuracy, like a football - while also forming a seal to ensure the pressure of gasses behind the projectile remained contained for maximum velocity). Eventually the rifling would be worn down enough that gasses would leak, velocity would decrease, and spin would be less stable - decreasing accuracy of the shot. Each shot was tracked by personnel within the gun turret, for each barrel, even in practice and training shooting. Once a gun was worn out and removed from the turret, a manufacturing facility - such as the gun factory at Washington Navy Yard - could remove the rifling and replace it, since the rifling was designed as an insertable liner rather than molded into the gun barrel's interior wall.