Rotating gas-check

A rotating gas-check (more commonly known as an automatic gas-check) was a copper plate that automatically attached itself to a specially-designed studless projectile of rifled muzzle-loading ("RML") artillery, sealing the escape of gas between the projectile and the barrel and imparting axial rotation to the projectile.

Gallery

 * 1) RML 12.5in Studless Palliser Shell Mk I with Automatic Gas-Check
 * 2) RML 12.5in Studless Common Shell Mk I with Automatic Gas-Check