AN IMPROVED METHOD OF RIFLING OR GROOVING THE BARRELS OF FIRE-ARMS AND ORDNANCE
Year: 1861

page_text: LETTERS PATENT to Robert Scott, of 29, Great Portland Street, in
the County of Middlesex, Gun Maker, for the Invention of "AN
IMPROVED METHOD OF RIFLING OR GROOVING THE BARRELS OF FIRE-ARMS
AND ORDNANCE."
Sealed the 13th June 1862, and dated the 18th December 1861.
PROVISIONAL SPECIFICATION left by the said Robert Scott at the
Office of the Commissioners of Patents, with his Petition, on-the 18th
December 1861.
I, ROBERT SCOTT, of 29, Great Portland Street, in the County of Middlesex,
Gun Maker, do hereby declare the nature of the said Invention for "AN
IMPROVED METHOD OF RIFLING OR GROOVING THE BARRELS OF FIRE-ARMS AND
ORDNANCE," to be as follows:-
The cutting the grooves in such manner as to present the smoothest possible
surface to the projectile, in order to approximate as closely as practical to the
cylindrical smooth bore, but at the same time giving sufficient variation from
the cylindrical form to insure the projectile following the curved run of the
grooves without stripping. I effect this by giving to the grooves the cross
sectional form of an arc of a circle, the radius of the arc being rather less than
that of the interior surface of the barrel.
The accompanying Drawing represents the cross section of a barrel rifled
according to this Invention. The firm lines show the form of the barrel
when grooved, and the dotted circle the interior surface of the barrel before
grooving.

page_text: The points a, b, and c, marking the centres from which the grooves are
struck, and the points d, e, and f, where the arcs meet and cut into the
interior surface of the barrel, mark respectively the angles of concentric
equilateral triangles. The whole of the interior surface of the barrel is
occupied by the three grooves, no space or lands being left between them.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Robert Scott in the Great Seal Patent Office on the 18th
June 1862.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ROBERT
SCOTT, of No. 29, Great Portland Street, in the County of Middlesex, Gun
Maker, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Eighteenth day of December, in the year of our
Lord One thousand eight hundred and sixty-one, in the twenty-fifth year of
Her reign, did, for Herself, Her heirs and successors, give and grant unto
me, the said Robert Scott, Her special license that I, the said Robert
Scott, my executors, administrators, and assigns, or such others as I,
the said Robert Scott, my executors, administrators, and assigns, should
at any time agree with, and no others, from time to time and at all times
thereafter during the term therein expressed, should and lawfully might
make, use, exercise, and vend, within the United Kingdom of Great Britain
and Ireland, the Channel Islands, and Isle of Man, an Invention for "AN
IMPROVED METHOD OF RIFLING OR GROOVING THE BARRELS OF FIRE-ARMS AND
ORDNANCE," upon the condition (amongst others) that I, the said Robert
Scott, by an instrument in writing under my hand and seal, should par-
ticularly describe and ascertain the nature of the said Invention, and in
what manner the same was to be performed, and cause the same to be filed
in the Great Seal Patent Office within six calendar months next and imme-
diately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Robert Scott, hereby declare the
nature of my said Invention, and in what manner the same is to be performed,
to be particularly described and ascertained in and by the following statement
(that is to say)
The cutting the longitudinal spiral grooves along the interior surface of the
barrels of rifles and ordnance in such manner as to present the smoothest
possible surface to the projectile, in order to approximate as closely as practical

page_text: to the cylindrical smooth bore, but at the same time giving sufficient variation
from the cylindrical form, to insure the projectile following the curved run of
the grooves without stripping. I am aware this has been attempted by
Lancaster, Jones, and others, but has in all cases partially failed, owing to the
grooves either running tangentially into the interior surface of the barrel, or
joining each other by reversed curves, such forms not having sufficient grip of
the projectile to prevent stripping. I effect my object by giving to the grooves
the cross sectional form of an arc of a circle, the radius of the arc being rather
less than that of the interior surface of the barrel previous to grooving; the
grooves when cut occupy the whole of the interior surface of the barrel, the
sides of the grooves intersect each other as they meet the interior cylindrical
surface of the barrel. These points of intersection thus form raised angular
lands running spirally down the barrel, and are the only lines of the interior
surface of the barrel not cut away in the process of rifling.
The accompanying Drawing represents a cross section of a barrel rifled
according to my Invention, the firm lines shew the form of the barrel when
grooved, and the dotted circle the interior surface of the cylindrical bored
barrel previous to being grooved or rifled.
a, b, and c shew the centres from which the arc grooves are struck, and
d, e, and f, the points where the edges of the grooves intersect each other, and
meet the interior cylindrical surface of the barrel, these latter points forming
the continuous raised lands previously described. I prefer the grooves to be
in cross sectional form, arcs of circles, as described, but I do not confine
myself to that particular form of curve.
I claim as my Invention, the construction of the grooves of fire-arms and
ordnance with the edges of the curved grooves intersecting each other as they
meet the interior surface of the barrel, and forming at the points of inter-
section raised angular lands running spirally along the interior surface of
the barrel.
In witness whereof, I, the said Robert Scott, have hereunto set my
hand and seal, this Seventeenth day of June, in the year of our
Lord One thousand eight hundred and sixty-two.
ROBERT SCOTT. (L.S.)
Witness,
EDWARD J. POWELL.