Federal

Parrott

 

DIAMETER: 7.9 inches
GUN: 200-pounder Parrott Rifle, 8-inch Caliber
LENGTH: About 19 3/4 inches
WEIGHT: About 155 pounds
CONSTRUCTION: Common Shell
SABOT: Brass, Type 1
FUZING: Water Cap Fuze Plug

A typical specimen of this very large projectile.  This is the "long" version.