Year: 1886

page_text: Date of Application, 10th May, 1886.
Complete Left, 9th Feb., 1887.
Complete Accepted, 6th May, 1887.
I JOSIAH VAVASSEUR of the London Ordnance Works, Bear Lane, Southwark in
the County of Surrey Engineer do hereby declare the nature of this invention to be as
follows:-
This Invention has for its object improvements relating to projectiles for ordnance.
At present it is usual to make projectiles for ordnance flat at the base. When
however projectiles of this form are fired it is found that the pressure upon the walls
of the gun is considerably more severe than it is upon the base of the projectile; also
that erosion of the bore takes place.
To remove or lessen these inconveniences I make the base of the projectile of cup
form or concave so that the powder gases impinging upon it may be reflected inwards
towards the axis of the bore and not outwards against the walls of the gun.
The concavity is formed in the rigid material of which the body of the projectile is
formed or in an equally rigid adjunct.
The cup or concavity is not intended to expand or change its form on firing or to
enter into the grooves of the rifling as was the case with the cups formerly employed
with the entirely different objects of preventing windage and rotating the projectile.
Such expanding cups have been found to interfere with the accuracy of the shooting
and I do not employ them.
CARPMAEL & Co.,
Agents for the Applicant.

page_text: COMPLETE SPECIFICATION.
Improvements relating to Projectiles for Ordnance.
I, JOSIAH VAVASSEUR of the London Ordnance Works, Bear Lane, Southwark,
in the County of Surrey, Engineer, do hereby declare the nature of this invention
and in what manner the same is to be performed to be particularly described and
ascertained in and by the following statement :-
This invention has for its object improvements relating to projectiles for ordnance.
At present it is usual to make projectiles for ordnance flat at the base. When
however projectiles of this form are fired it is found that the pressure upon the walls
of the gun is considerably more severe than it is upon the base of the projectile; also
that crosion of the bore takes place.
To remove or lessen these inconveniences I make the base of the projectile of cup
form or concave so that the powder gases impinging upon it may he reflected inwards
towards the axis of the bore and not outwards against the walls of the gun.
The concavity is formed in the rigid material of which the body of the projectile is
formed or in an equally rigid adjunct.
The cup or concavity is not intended to expand or change its form on firing or to
enter into the grooves of the rifling as was the case with the cups formerly employed
with the entirely different objects of preventing windage and rotating the projectile.
Such expanding cups have been found to interfere with the accuracy of the shooting
and I do not employ them.
A longitudinal section of a projectile formed in accordance with my invention is
represented by the annexed drawing.
Having now particularly described and ascertained the nature of my said invention
and in what manner the same is to be performed I declare that what I claim is :-
A projectile for ordnance having a rigid cup like base substantially as and for the
purpose described.