Federal

Butler

 

DIAMETER:  2.96 inches
GUN:  3-inch wrought iron (ordnance) rifle
LENGTH:  8 1/2 inches
WEIGHT:  9 pounds 14 ounces
CONSTRUCTION:  Shell
SABOT:  Brass ring, Butler's patent
FUZING:  Threaded time fuze plug (missing)
This projectile appears to be a variant of the Federal Absterdam.  However, patent information suggests that the sabot is most likely covered under the Butler patent on figure III B-5.  Whatever the precise origin, this projectile was never combat proven.  Note the four flame grooves that run the entire length of the projectile body.  The brass sabot has the impressions of the seven lands and grooves of the Federal 3-inch wrought iron (ordnance) rifle.