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.
