the United States,
residing at New York city, county of New York, and State of New York,
have invented certain new and useful Improvements in Projectiles, of
which the following is a specification.

My invention, relates to an improved form of explosive shell or other
projectile, and more particularly to those projectiles which are
reinforced by longitudinal ribs.

It further relates to a method whereby such a projectile may be made.

The object of my invention is to provide a shell having a maximum
strength or perforating power, together with a maximum capacity for an
explosive charge, and the invention consists in forming the projectile
with the fibers or grain of the metal running in a spiral direction
from the base of the shell to the top thereof, and in reinforcing the
interior of the shell with ribs which shall run in the same direction,
starting at the base of the projectile and ending at the top end of the
inner chamber.

In the drawings, Figure 1 is a side view of a projectile, the grain or
fiber of which is indicated by dotted lines. Fig. 2 is a longitudinal
section showing the interior ribs. Fig. 3 is a transverse section on
the line 3--3, Fig. 2.

While the tendency to rupture is very much lessened by the use of
straight longitudinal ribs on the interior of shells and projectiles of
various kinds, yet such a straight longitudinal rib is itself liable to
a sheering and disruptive stress along transverse lines when the
projectile strikes, due to the rotative inertia of the projectile in
its flight.

The aim of my invention is to provide ribs which will be coincident
with the rotative travel of the shell so that when the point of the
projectile enters an armor plate, the stress of this sudden stoppage of
rotation will be taken up along the fiber or grain of the shell and by
the spiral ribs therein. Thus the sheering tendency of the metal in the
walls of the shell is greatly reduced and greater strength is given to
resist the tendency of the rear end of the shell to twist off, due to
the rotatory course when the head of the shell is embedded in an armor
plate.

Like letters in the figures designate like parts.

A represents the shell, and B the fuse, B' being the rotating band
which is secured on the shell near the base in the usual way. The
hollow portion of the shell consists of a chamber C extending from the
base to the forward end of the shell. The walls of this chamber are
provided with the ribs