Built-up gun

A built-up gun is artillery with a specially reinforced barrel. An inner tube of metal stretches within its elastic limit under the pressure of confined powder gases to transmit stress to outer cylinders that are under tension.^[1] Concentric metal cylinders or wire windings are assembled to minimize the weight required to resist the pressure of powder gases pushing a projectile out of the barrel. Built-up construction was the norm for guns mounted aboard 20th century dreadnoughts and contemporary railway guns, coastal artillery, and siege guns through World War II.