I- PROVEMENTS IN FIRE-ARMS
Year: 1856

page_text: LETTERS PATENT to John Henry Johnson, of 47, Lincoln's Inn Fields,
in the County of Middlesex, and of 166, Buchanan Street, in the
City of Glasgow, North Britain, Gentleman, for the Invention of "I-
PROVEMENTS IN FIRE-ARMS."-A communication from Gaun M. Hutton,
Citizen of the United States, now acting as Vice-Consul for the United
CC Dotorchurch in the Empire of Russia.
PROVISIONAL SPECIFICATION left by the said John Henry Johnson
at the Office of the Commissioners of Patents, with his Petition, on the
13th September 1856.
I, JOHN HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County of
Middlesex, and of 166, Buchanan Street, in the City of Glasgow, North
Britain, Gentleman, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN FIRE-ARMS," a communication from Gaun M. Hutton, Citizen
of the United States, now acting as Vice-Consul for the United States at
St. Petersburg, in the Empire of Russia, to be as follows:-
This Invention relates to various improvements in fire-arms or artillery,
whereby such weapons are rendered more accurate and efficient in their
action than those hitherto in use. The present improvements refer more par-
ticularly to rifled cannon, and consists in producing the rifle grooves in a
peculiar manner.

page_text: In carrying out the Invention, the back or inner end of each rifle groove
is ground or filed into the metal of the bore by means of a cast-steel wheel,
the edge or face of which has a cross section corresponding to the deepest
part of the groove, but a little larger. This wheel is driven by means of a
cord and pulleys, or in any other convenient manner, and is pressed against
the side of the bore by means of springs or otherwise. The rifle grooves are
subsequently completed by means of traversing cutters, acting as in a planing
machine, and being set out by a wedge drawn between them by a rod issuing
at the muzzle of the piece. It is preferred to cut the rifle grooves so that
their depth in the metal of the bore shall gradually diminish towards the
muzzle, and the depth of the cut is regulated by means of an arm, projecting
laterally and resting or sliding upon an inclined or curved guide. This arm
or lever acts on the nut which draws in the rod attached to the wedge, by
means of which the cutters are adjusted.
The object of first cutting out the inner ends of the grooves as described is
for the rifling tool, subsequently used, to run out into a clear open space, so as
to take its new position for a clean firm cut. When the cannon is rifled with
twelve grooves, the grooves taking up about one-half the surface of the bore,
and being each about one-fiftieth of a calibre in depth, with a cross section of
circular outline, a very good result is obtained, but it is preferred to adopt a
smaller number of grooves, each of proportionately larger size.
It is preferred not to extend the grooving further back or inwards in the
piece than a point corresponding with the back of the projectile when in
position for firing, so as to leave the full strength of the metal around and a
little in front of the charge of powder. As both the bore and the rifle grooves
are liable to be imperfect just at the muzzle of the piece, it is intended to cast
the piece with an extra thickness of metal, equal, say, to about one-tenth of a
calibre, to be turned off the muzzle after grooving. For a similar reason,
and also to facilitate loading, the muzzle is countersunk or bevilled on its
inner edge to the full depth of the grooves, or a little more, the bevil fitting
a cone, the height of which is about three times the diameter of its base.
The degree of twist, or the pitch of the rifle grooves, may be modified to
suit the kind of projectile used, and it is preferred to make the twist or pitch
differential, the twist increasing or the pitch diminishing towards the muzzle
of the piece. A final twist or pitch at the muzzle, equal to one turn in about
two hundred and fifty calibres for light charges, or one turn in three hundred
calibres with strong charges, gives a good result.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said John Henry Johnson in the Great Seal Patent Office on
the 13th March 1857.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County of Middlesex,
and of 166, Buchanan Street, in the City of Glasgow, North Britain, Gentle-
man, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, Iler Letters
Patent, bearing date the Thirteenth day of September, in the year of our Lord
One thousand eight hundred and fifty-six, in the twentieth year of Her reign,
did, for Herself, Her heirs and successors, give and grant unto me, the said
John Henry Johnson, Her special license that I, the said John Henry
Johnson, my executors, administrators, and assigns, or such others as I,
the said John Henry Johnson, my executors, administrators, or 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
"IMPROVEMENTS IN FIRE-ARMS," a communication from Gaun M. Hutton, Citizen
of the United States, now acting as Vice-Consul for the United States at
St. Petersburg, in the Empire of Russia, upon the condition (amongst others)
that I, the said John Henry Johnson, by an instrument in writing under my
hand and seal, should particularly describe and ascertain the nature of the
said Invention, and in what manner the same was to be per.ormed, and
cause the same to be filed in the Great Seal Patent Office within six calendar
months next and immediately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said John Henry Johnson, do hereby declare
the nature of the said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement, reference being had to the accompanying Drawings, and to the
letters and figures marked thereon, that is to say :-
The said Invention relates to various improvements in fire-arms or artillery,
whereby such weapons are rendered more accurate and efficient in their action
than those hitherto in use. A portion of the present improvements refer more
particularly to rifled cannon, and consists in producing the rifle grooves in a
peculiar manner.
In carrying out this part of the Invention, the back end of each rifle groove

page_text: is ground or filed into the metal of the bore by means of a cast-steel wheel,
the edge or face of which has a cross section corresponding to the deepest
part of the groove, but a little larger. This wheel is driven by means of a cord
and pulleys, or in any other convenient manner, and is pressed against the
side of the bore by means of springs or otherwise. The rifle grooves are
subsequently completed by means of traversing cutters acting as in a planing
machine, and being set out by a wedge drawn between them by a rod issuing
at the muzzle of the piece. It is preferred to cut the rifle grooves so that
their depth in the metal of the bore shall gradually diminish towards the
muzzle, and the depth of the cut is regulated by means of an arm, projecting
laterally and resting or sliding upon an inclined or curved guide. This
arm or lever acts on the nut, which draws in the rod attached to the wedge,
by means of which the cutters are adjusted.
The object of first cutting out the inner ends of the grooves as described is
to enable the rifling tool, subsequently used, to run out into a clear open space,
so as to take its new position for a clean firm cut. When the cannon is
rifled with twelve grooves, the grooves taking up about one-half the surface of
the bore, and being each about one-fiftieth of a calibre in depth, with a cross
section of circular outline, a very good result is obtained, but it is preferred to
adopt a smaller number of grooves of proportionately larger size.
It is preferred not to extend the grooving further back or inwards in the
piece than a point corresponding with the back of the projectile when in
position for firing, so as to leave the full strength of the metal around, and
a little in front of the charge of powder. As both the bore and the rifle
grooves are liable to be imperfect just at the muzzle of the piece, it is intended
to cast the piece with an extra thickness of metal, equal, say, to about one-
tenth of a calibre, to be turned off the muzzle after grooving. For a similar
reason, and also to facilitate loading, the muzzle is countersunk or bevilled on
the inner edge to the full depth of the grooves, or a little more, the bevil fitting
a cone, the height of which is about three times the diameter of its base.
The degree of twist, or the pitch of the rifle grooves, may be modified to suit
the kind of projectile used, and it is preferred to make the twist or pitch
differential, the twist increasing or the pitch diminishing towards the muzzle
of the piece. A final twist or pitch at the muzzle, equal to one turn in about
two hundred and fifty calibres for light charges, or one turn in three hundred
calibres with strong charges, gives a good result.
And in order that the said Invention may be clearly understood, I shall now
proceed more particularly to describe the same, and for that purpose I shall
refer to the several Figures on the Sheets of Drawings hereunto annexed, the

page_text: same letters of reference indicating corresponding parts throughout all the
corresponding Figures.
Figure 1 on Sheet 1 of the Drawings represents a longitudinal vertical
section of a cannon whilst undergoing the first operation, preparatory to
grooving or rifling, which operation consists in grinding or filing the back or
breech end of each groove into the metal of the bore by means of a cast steel
or revolving file; Figure 2 is a corresponding horizontal section of the
same. Figure 3 is a front elevation of the supporting standards and bed
plate. Figure 4 is an enlarged elevational detail of the circular cutter and
mechanism connected therewith; and Figure 5 is a corresponding plan of the
same.
A is the gun which is to be rifled; it is accurately fitted in bearings in the
two fixed standards B, C, on the foundations D, D. A worm wheel E is
keyed on to the muzzle end of the gun, and gears with the worm F, which
imparts the requisite motion to the gun for adjusting or turning it in its
bearings, so as to present different portions of the internal surface of the bore
to the action of the circular cutter G, which I shall herein-after fully describe.
Suitable indices or divided plates or discs II are employed for the purpose of
enabling the number and position of the grooves to be accurately determined.
The circular cutter G in contained in a slot or opening near one end of the
mandril I, which carries a circular end piece K fitting the bore of the piece,
so that the mandril may always be held in the axial line of the bore. The
other end of the mandril is retained concentrically to the bore at the muzzle
by means of the collar L, which fits the muzzle of the gun. The spindle of
the cutter G carries a spur wheel, which receives motion by means of the train
of gearing M from the spindle N. This spindle carries a grooved pulley O,
round which is passed the endless band P (shewn in red lines); this band
receives its motion from the pulley Q at the outer end of the mandril, which
pulley is rotated by the hand wheel and handle R. The spindle which carries
the cutter G works in sliding bearings S, which are pressed downwards, so as
to cause the cutter to enter the metal by means of the two blade springs T, T.
The depth of cut is regulated by means of two bell-crank levers U, U, the
horizontal arms of which project beneath the bearings S, whilst their vertical
arms are attached to the rods V, V. These rods are screwed at their opposite
ends, and are adjusted by means of the thumb nuts W, W.
In cutting the recesses, by this apparatus, the mandril with its cutter is
introduced into the gun, as shewn in Figures 1 and 2, until the circular end
piece K is driven home to the breech; the position of the first groove or recess
baving been determined, and the mandril properly adjusted, the hand wheel R

page_text: is rotated, whereby a rotatory motion is imparted to the circular wheel cutter
G, which is pressed down as fast as it cuts away the metal by the springs T, T,
until the requisite depth is attained; the cutter is then elevated or raised out
of its cut by drawing or screwing up the rods V, V. The gun is now rotated
by means of the worm and worm wheel, herein-before referred to, a distance
corresponding to the space between the grooves to be produced, which distance
will be accurately determined by the divided plates or indices herein-before
referred to, and the operation of cutting is repeated in this manner until the
breech ends of the whole of the grooves to be made are cut out or recessed;
the mandril and cutter are now withdrawn, and the gun is subjected to the
rifling process, which I shall proceed to describe in reference to Sheet 2 of the
Drawings.
Figure 1 on Sheet 2 of the Drawings represents a longitudinal vertical
section of a gun whilst undergoing the second process, namely, that of rifling
the bore; and Figure 2 is a sectional plan of the same. The rest of the
Figures are enlarged details, which I shall herein-after more fully describe.
The rifling of the bore is effected in the same machine in which the recesses
were cut by the circular cutter G, herein-before referred to. The tool which
I propose to employ for cutting the grooves consists of a cutter head I (shewn
more clearly in the enlarged detail, sectional elevation, and plan, at Figures (3
and 4), in which cutter head are fitted two chisel-edged cutters K, K. These
cutters are caused to expand or contract, so as to produce a greater or less
depth of cut, by means of the double wedge piece L, which is grooved to
receive the bottoms of cutters, and is fixed on to one end of the rod M,
which is contained inside the tube N carrying the cutter head. This tube is
fitted into the cast-iron cylinder 0 (shewn in transverse section at Figures 5
and 6) upon the surface of which are screwed the spiral guide rods or bars
P, P, for the purpose of giving the requisite twist to the grooves; these
guide rods or bars can be readily shifted, or they can be replaced by others of
a greater or less twist, or of a differential twist, as found desirable; they fit
into corresponding grooves in the stationary standard or support C'. The
cylinder O has a collar formed upon it at its extreme outer end, and this collar
is embraced by the bearing Q in the standard R, carried by the traversing
planing machine bed plate D¹. It will thus be obvious, that as the cylinder
O is drawn through the fixed standard C', a rotatory or a partial rotatory
motion will be imparted to it, and thence to the grooving cutter head, thereby
producing, in combination with the rectlinear motion of the bed plate, the
requisite twist of the rifle grooves. The rod M, which regulates the depth of
the grooves, has a screw thread formed upon it at its outer end, which

page_text: screwed portion works through the nut or internal screwed collar S. I prefer
making this nut by casting Babbit metal round the screw on the rod. As I
consider it highly advantageous to cause the depth of the grooves to diminish
gradually towards the muzzle of the gun, I propose to employ an arrangement
of apparatus whereby the cutters K, K, shall be permitted gradually to con-
tract or close into the cutter head as they approach the muzzle. I accomplish
this by means of the arms T connected with the nut S. This arm stands out
laterally, so as to rest upon the fixed incline U. On commencing the stroke,
that is to say, when the cutter head is at the breach of the gun, the arm T
will be at the bottom of the incline, and will gradually rise up it during the
outward traverse of the bed plate D¹. This produces a partial rotation of the
nut S, and causes the rod M to move inwards and push back the wedge L,
thereby admitting of the gradual contraction of the cutters, and consequent
diminishing depth of grooves. The connection of the arm T with the nut S
is effected by means of the set screws, so that it may readily be loosened
when it is requisite to set out the cutters for the succeeding deeper cut, which
is accomplished by turning more or less the nut S, so as to draw the wedge
piece L inwards, and thereby expand the cutters. By having recesses ground
or cut into the bore at the commencement of each groove, as described with
reference to Sheet 1 of the Drawings, the grooving or rifling tools or cutters
are always enabled to run back into a clear space, so as to take a new position
for a clean firm cut; this constituting one of the main features of the present
Invention.
Figure 1 on Sheet 3 of the Drawings represents a full-sized transverse
section, taken through the muzzle end of the gun; Figure 2 is a longitudinal
section of the same; and Figure 3 is a transverse section, taken through the
breech end of the gun. It will be clearly seen, on comparing the views 1 and
3, that the back or breech end of the grooves is deeper than the muzzle end.
In Figure 1 the dotted curves represent the increased depth of the breech end
of the grooves. Each groove is about one-fiftieth of a calibre in depth at the
breech, and its cross section is an arc of a circle. Although twelve grooves
produce a good result, I prefer a smaller number, and wider grooves in
proportion. I prefer also not to extend the grooving further back than about
flush or square with the hinder part of the projectile when the piece is loaded,
so as to leave the full strength of the metal around and a little in advance of
the charge, and I also cause the breech end of the groove to run out into
the surface of the bore.
As both the bore and the grooves are liable to be imperfect immediately at
the edge of the muzzle of the piece, I prefer to leave about half an inch of

page_text: extra metal, to be turned off the end of the muzzle after grooving, and for the
same reason, and to facilitate the loading of the piece, I countersink the muzzle
in all cases to the full depth of the grooves, as shewn in Figure 2, such
countersinking corresponding to a cone whose height is about three times the
diameter of its base. Figure 4 represents a plano projection of the grooves,
shewing the amount of twist or deflection which I prefer; and Figures 5 and
6 are diagram views of the breech and muzzle ends of the gun respectively,
drawn to the same scale as the projection, Figure 4.
For the purpose of obtaining greater strength and economy, I propose to
use a stronger and less brittle material than ordinary cast iron, and the com-
pounds intermediate between steel and iron.
Although I have merely represented my improvements as applied to the
manufacture of rifled ordnance, it will be obvious to the practical man that
such improvements are also applicable to the grooving or rifling of the barrels
of small arms.
Having now described and particularly ascertained the nature of the said
Invention, and the manner in which the same is or may be used or carried into
effect, I would observe, in conclusion, that I do not confine or restrict myself
to the precise details or arrangements which I have had occasion to describe
or refer to, as many variations may be made therefrom without deviating from
the principles or main features of the said Invention; but what I consider to be
novel and original, and therefore claim as the Invention secured to me by the
herein-before in part recited Letters Patent, is,-
First, the general constructions and arrangements of fire-arms and ordnance,
as herein-before described.
Second, the cutting of a recess or chamber at the commencement of each
groove previous to rifling the gun, for the purpose of enabling the rifling tool
to run back into a clear space and make a firm clean cut at each succeeding
stroke.
Third, the application and use of a circular cutter or file for the purpose of
cutting a recess or chamber at the conimencement of each groove previous to
rifling the gun.
Fourth, the system or mode of producing rifle grooves of a gradually
diminishing depth towards the muzzle, when the rifling tool is allowed to run
back into a recess or chamber previously formed in the gun for that purpose,
as herein-before described.
Fifth, the peculiar construction and arrangement of expanding and con-
tracting rifling tool for cutting grooves of a gradually diminishing depth
towards the muzzle, as herein-before described.

page_text: Sixth, the application and use of an arm resting upon an inclined or curved
guide for the purpose of gradually contracting the rifling cutters, as herein-
before described.
In witness whereof, I, the said John Henry Johnson, have hereunto set
ny hand and seal, the Thirteenth day of March, One thousand eight
hundred and fifty-seven.
J. HENRY JOHNSON. (L.S.)