CERTAIN IMPROVEMENTS IN RIFLING APPLICABLE TO EITHER BREECH OR MUZZLE LOADING FIRE-ARMS OR ORDNANCE
Year: 1860

page_text: LETTERS PATENT to Thomas Turner, Gun Manufacturer, of Fisher Street,
Birmingham, in the County of Warwick, for the Invention of "CERTAIN
IMPROVEMENTS IN RIFLING APPLICABLE TO EITHER BREECH OR MUZZLE LOADING
FIRE-ARMS OR ORDNANCE."
Sealed the 29th June 1860, and dated the 16th April 1860.
PROVISIONAL SPECIFICATION left by the said Thomas Turner, at tho
Office of the Commissioners of Patents, with his Petition, on the
16th April 1860.
I, THOMAS TURNER, Gun Mauufacturer, of Fisher Street, Birmingham, in
the County of Warwick, do hereby declare the nature of my said Invention
for "CERTAIN IMPROVEMENTS IN RIFLING APPLICABLE TO EITHER BREECH OR MUZZLE
LOADING FIRE-ARMS OR ORDNANCE," to be as follows (that is to say):
My improvements in rifling consist in sinking the grooves parallel from
the muzzle through about six-tenths, more or less, as may be desired, of
the length of the gun barrel or cannon 1 wish to rifle, and from there to
the breech I gradually increase the depth of the grooves, the edges of
which instead of being at right angles, as heretofore, I prefer to be bevilled
at an angle of about forty-five degrees; the advantages of this plan are very
great, as the act of loading may be done with the same case and facility

page_text: with which rifled fire-arms are now loaded, but in consequence of the quicker
contraction of the barrel from the breech and the natural expansion of the
ball in front of the charge, so impinges the barrel through the part that
usually becomes foul, that all fouling left from the preceding charge is
carried away by the one following, and I effect this improved system of
rifling by so fashioning the rod that regulates the cutter that according to
the amount of inclination to be imparted to the rifling towards the breech
so is the rod more or less twisted, the spiral of the twist increasing as the
rifling deepeus, and in rifling that portion from the apex of the incline to
the muzzle, the rod that regulates the cutter (before referred to) is twisted
in the reverse direction, the twist or spiral being perfectly regular, by
which means the rifling through that portion is left perfectly parallel.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Thomas Turner in the Great Seal Patent Office on the
16th October 1860.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, THOMAS
TURNER, Gun Manufacturer, of Fisher Street, Birmingham, in the County
of Warwick, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Sixteenth day of April, in the year of our
Lord One thousand eight hundred and sixty, in the twenty-third year of
Her reign, did, for Herself, Her heirs and successors, give and grant unto
me, the said 'Thomas Turner, Her special license that I, the said Thomas
Turner, my executors, administrators, and assigns, or such others as I, the
said Thomas Iurner, 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 Mau, an Invention for "CERTAIN IMPROVE
MENTS IN RIFLING APPLICABLE TO EITHER BREECH OR MUZZLE LOADING FIRE
ARMS OR ORDNANCE," upon the condition (amongst others) that I, the said
Thomas Turner, 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 performed, 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.

page_text: NOW KNOW YE, that I, the said Thomas Turner, do 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 fol-
lowing statement (that is to say) :-
My improvements in rifling gun barrels and ordnance have for their object
the prevention of fouling common to the present mode of rifling, and this
I effect by cutting the grooves of irregular depths, as, for instance, from the
breech to about one-third of the length of the piece, more or less, I diminish
the depth of the grooves, and from there to the muzzle. I form my grooves
of a uniform depth; the number of the grooves, and the spiral form in which
they may be cut, may be varied as required, and instead of the angles of my
grooves being at right angles with the base line of the cutter (by which they
are formed, as now commonly adopted), I prefer making the angles of my
cutter, and consequently the grooves or lands formed by it, about thirty-five
degrees, more or less, with the base line of the cutter; by this means the
face of the lands from the breech to about one-third, more or less, of the
length, as desired, will increase in width as the depths of the grooves decrease,
and from there to the muzzle the face or front of the lauds or bore of the gun
will be perfectly uniform. This forms the main feature of my Invention, but
which may be variously modified, and yet obtain the object sought, namely,
the prevention of fouling, as, for instance, the portion occupied by the charge
may be formed parallel, and from there the grooves may be slightly decreased
in depth through the one-third of its spiral length, and from there to the
muzzle parallel, as before desc.ibed; or the grooving through the one-third
portion of the length of the rifling, instead of progressively decreasing in such
a way that the deepening shall form a straight line from the one-third portion
to the breech, it may be sunk, so as to form a slightly curved line, or the
portion of the rifling at the breech end may be nearly parallel, say one quarter,
more or less, through its length terminating with a curve to the parallel
portion of its rifling through the remainder of the bore to the muzzle. By
this system the ball or bullet, on receiving the expansive force of the gas (in
discharging the piece),will expand (ifproperly made and of suitable materials),
so as to fill up the grooves and volume of the bore, and as it is pressed
forward it becomes impinged by the contraction of the rifling, so that it carries
before it all fouling left from the preceding charge; thus it matters not how
rapidly a piece (so rifled) may be fired, no objectionable fouling can possibly
take place, and the pieco will be found ready at all times for use, without
requiring cleaning or sponging unless it becomes foul from other cause or
cau-es than that herein before stated.

page_text: I have not thought it necessary to lay down any rule for the pitch of the
spinal of the rifling, as that may vary according to the size of the bore and
the length of the projectile.
.
I effect this system of rifling in the following way :-For a bore of about 453
of one thousand parts of an inch, with, say, five cuts, which is a guage of bore
and form of rifling commonly used, I commence in the in the following way:
Supposing the barrel to be fixed on a cast-iron frame, with bearings for the
nut or socket for the rifling rod to slide through, which may be drawn through
the socket by a screw or rack pinion or other convenient means, with a
circular boss or socket fixed on the end of the barrel, and divided on its
periphery into the requisite number of grooves to be formed in the barrel.
This boss is held by a spring, which permits of its being turned around when
required, and held in its stated divided positions. The cutter is held in a
tubular holder, which tubular holder is attached by screwing or otherwise to
the rifling rod, against the end of which a spiral spring abuts and exerts its
force against a plug, which plug presses against a cutter, and the other end of
the cutter is further held by a slide, which is kept in position by a left-handed
screw, the head or end of which projects out from the tubular cutter holder,
and is divided and tapped for connecting it with the following rod, the con-
nection being formed by a tapped collar working over the end of the set screw,
and the tapped end of the following rod, which passes through a hollow
spindle in which it slides. This following rod is square, and twisted with a
left-hand spiral at its end towards the cutter, the spiral decreasing in pitch
until it ceases, and then commences to turn spirally to the right hand, which
increases until it reaches a twenty-inch pitch, and continues the same to the
end of the rod, that part of the following rod being the same spiral as the
rifling rod. The action of the following rod on the rifling tool will be under-
stood from the following description: As the cutter is pulled through the
barrel from the breech towards the muzzle, deriving its spiral motion from the
spiral twist of the rifling rod, the following rod is made to turn, thereby
operating on the screw that regulates the cutter, the end of which working on
an inclined plane causes it to be depressed more or less in a radial direction,
according to the twist of the following rod as the cutter is taken through the
bore, and the spiral spring, which counteracts the reversing action of the
following or adjusting rod. But as the description of my Invention will be
better understood aided by the Drawings hereunto annexed, I will proceed to
describe the same, reference being made to the figures and letters marked
thereon.

page_text: DESCRIPTION OF DRAWING.
Fig. 1 is a longitudinal sectional view of the cutter holder, which slides
with the cutter through the barrel during the operation of rifling; the rifling
rod is attached to the holder at A, and against the end of this rod the spiral
spring abuts, exerting its force against the plug B, which forces the inclined
end of the cutter C up the incline D, causing the working portion of the
cutter to extend in a radial direction, more or less, according to the counter-
acting position of the sliding plug E, which is actuated by the screw F, and
which screw is united to the following rod by the tapped collar G, here-
after to be referred to. From this view it will be readily seen, that by
screwing or reversing the screw F the plug E will be pressed against the
end of the cutter, causing it to ascend or descend on the inclined plane.
And it is by this principle of shifting the cutter that I obtain the variation
in the depth of the groove formed by my system of rifling, which forms the
primary feature of my improvements.
Fig. 2 represents a top view of Figure 1, showing the groove in the cutter
holder, by which the cutter C is applied and withdrawn.
And Fig. 3 represents a portion of the following rod, re-senting the way
of attaching it to the regulating screw F of the cutter holder, namely, by
uniting the parts together at the halving and screwing the collar G over them
both. The following rod is represented, for convenience of space, as divided
into three parts, namely, H, of Fig. 4, should form a continuation of I,
Figure 3; aud J, Fig. 5, a continuation of K, Figure 4, thus showing the
entire length of the following rod, drawn full size, for rifling a gun barrel of
the bore before named, and the spiral of the rod calculated to produce the
graduated deepening of the barrel from about of one-third of its length from
the breech, and parallel through the remaining portion; and this is effected
by the cutter holder partaking of a spiral motion with the cutter through the
barrel in cutting the grooves, from the holder being attached to the rifling rod,
which being pulled through a fixed hole imparts the same spiral curve to the
cutter that is given to the rifling rod; and the following rod passing also
through a square hole in a fixed collar causes it to turn according to the
spiral, and this spiral action of the following rod turns the screw F from
right to left, thereby pressing forward the cutter towards the rifling rod and
down its inclined bed, diminishing its radial distance, and consequently
reducing the depth of the grooves formed by it, until it reaches the part of
the harrel, where it is desirable to form the groove parallel.
Fig. 6 represents the sectional part of a gun barrel necessary to further

page_text: illustrate my system of rifling. 1 represents the breech end of a gun barrel,
and from there to any given portion of its length, I purpose cutting the spiral
grooves deeper at the breech, and from the breech gradually shallower, either
progressively from the extreme breech to the approved distance along the
barrel, or by carrying the cutting process through the length that would be
occupied by the charge, parallel as here shown from M. to N, and from there,
say, to P, I gradually decrease the depth, and from P to the muzzle of the gun
perfectly parallel. Or, instead of sinking the spiral groove of the rifling of a
gradually decreased depth from N to P, I may sink it of a slightly curvilinear
shape, that is to say, allowing the difference of the base of the cut or groove
at N and P to form a part of a regular curve, without allowing the arc of the
curve to extend radially beyond the depth of the groove, as defined at N. Or,
the
grooves of the rifling may be sunk parallel, say, to Q, and from there to P,
to terminate the contraction in a curved form. The inner circle at R and the
inner circle at S are identical, and the difference between these concentric
circles and the outer ones represents the difference between the depth of the
lands at N and P, and the concentric circles at Fig. 7 represent the bore
and the depth of the lands at the muzzle and at the breech.
Fig. 8 represents an imaginary section drawn to an enlarged scale of the
breech end of a musket or a wrought iron or steel cannon; and Fig. 9 the
muzzle end section, the inner dotted circle in each being identical. These
two views represent the difference of the depth of the grooves of the riffing
at the breech and the muzzle end; and the part 'l' represents the cutter for
forming such grooves, showing the angle I prefer, for the sides of the grooves
or lands, which angle taken from the base line of the cutter at U, U, will be
found to be about thirty-five degrees. This form of angle induces a quicker
and fuller expansion of the ball, to completely fill up the whole volume or en-
tirety of the bore, so essential to my improvement, for removing all fouling left
from the preceding charge. The common defect with the ordinary system of
rifling, where the sides of the grooves form a right angle, with the base of the
cutter, as will be best seen by referring to Fig. 10, which represent an enlarged
section of a barrel rifled in the ordinary way, the cutter being represented at V,
and its base line at W,W. I have not thought proper to exhibit the general
description of machinery, with the detailed parts by which the rifling of guns
or ordnance is effected, because they are well known and understood by those
accustomed to the mechanical appliances for rifling, and which general appli-
ances I purpose using in effecting my improvements with the modifications
of the cutter holder and following rod herein described and exhibited.
And having now given a general description of my Invention, and the

page_text: manner which I believe will be found the most efficient for carrying the
same into effect, I wish it understood that what I claim and wish protected
by these my in part recited Letters Patent is,―
First, the rifling of the grooves so that the bottom of the grooves shall
be in a straight or curved or partly straight and partly curved spiral shape
from the breech to any determined part of gun barrels or ordnance, and
from the so determined part to the muzzle of equa depth.
Secondly, I claim the angular shape of the grooves or lands as exhibited
at Figures 8 and 9, in counter distinction to the shape of such grooves
hitherto made as exhibited at Figure 10, without purposing to confine
myself to any exact angle from a right angle to forty-five degrecs.
Thirdly, I claim the compound twisted following rod, without confining
myself to the direction the twist or spiral of such rod takes from or to the
tool holder.
And lastly, I claim the turning of the screw F, in the tool holder at a
variable speed, either right or left, during the process of rifling.
In witness whereof, I, the said Thomas Turner have hereunto set my
hand and seal, this Fifteenth day of October in the year of our
Lord One thousand eight hundred and sixty.
Witness,
JAMES S. COCKINGS, C. E.,
Patent Agent,
Birmingham.
THOMAS TURNER. (L.B.)