That damn cannon must have one hell of an ejector to throw a shell 3 miles!
I knew I should have read all the comments.
An artillery round of the type in this story consists of two basic parts...
1) Projectile - if explosive it is referred to as shell. If non explosive it is referred to as shot.
2) Cartridge Case or Casing - Ferrous or non ferrous metal canister containing propellant and ignition primer.
The terminology used in this story is correct.