The 1880s six-inch example shows built-up construction, with an inner tube reinforced by successive hoops and outer layers. Designers fitted those pieces under deliberate tension so they supported and stressed one another around the bore. When the propellant ignited, the combined structure had to contain its pressure instead of failing. Barrel strength depended on how several manufactured pieces worked together, making construction an applied-metallurgy problem.
Chapter · 21:13-22:30
Built-up gun barrels contained explosive pressure in layers
An 1880s built-up gun used successively fitted hoops and tubes under tension so the complete barrel could contain propellant pressure.