TARGET RANGE POCKET BOOK
FOR USE WSTH THE
U. S. MAGAZINE RIFLE
MODEL OF 1303. CAL. .30
APRIL 23, 1908
o
GIFT OF
XO. 1998
TARGET RANGE POCKET BOOK
FOR USE WITH THE
U. S. MAGAZINE RIFLE
MODEL OF 1903, CAL. .30
7 PLATES
\j\ .
APRIL 28, 1908
WASHINGTON
GOVERNMENT PRINTING OFFICE
1917
32
TARGET RANGE POCKET BOOK.
I. This pamphlet has been prepared especially for
use with the service rifle, model of 1903, on the target
range. The tables contained herein refer to the above-
mentioned rifle equipped with the model of 1905 sights,
graduated for the ball cartridge, caliber .30, model of
1906. The data given in the tables have been either
determined experimentally for the average rifle under
standard conditions or computed, using constants
obtained experimentally.
II. Blank columns have been left in the tables for
the addition of such data peculiar to any particular
rifle, as may be desired by the marksman. Great care
is taken in the manufacture of the rifle to insure its
uniformity and excellence, but so many variables enter
into the shooting of a rifle that a certain amount of
deviation from the average inevitably results.
III. The bore of the U. S. magazine rifle is drilled,
reamed, straightened, and rifled with the utmost of
mechanical and personal skill and the barrel is finally
stocked and targeted in order to test its actual shooting
qualities.
In targeting, each rifle is required, at a range of 200
yards, to place the center of impact of all shots well
within a vertical strip 7 inches wide. Too much care
can not be exercised in preserving the barrel and bore
of the rifle in good condition. The main points to be
observed are :
1. To keep the bore clean and well oiled so as to
avoid rust.
363418 8
4 TARGET RANGE POCKET BOOK.
2. To avoid the use in the bore of emery cloth or any
other harsh abrasive.
3. To protect the lips of the muzzle of the barrel
from deformation.
4. To protect the stock from moisture and consequent
swelling.
The above points are all important factors in the
good shooting of the rifle and should be carefully
observed by all who desire to obtain the best results.
IV. The following method of cleaning the bores of
small arms has been practiced at the Springfield Ar-
mory for a number of years with good results : As soon
as practicable after firing, using the brass cleaning rod
and cloth patches (preferably canton flannnel)
First. Thoroughly clean the bore with patches
soaked in a saturated solution of sal soda.
Second. Remove the soda from the bore, using dry
patches.
Third. Oil the bore, using patches saturated with
cosmic oil.
Fourth. About twenty-four hours after this cleaning
repeat the three operations just mentioned.
This second cleaning is necessary, no matter how
carefully the first cleaning is done, for the reason that
the powder gases are probably occluded by the steel
under the heavy chamber pressure and are not reached
by the first cleaning. .
After the second cleaning and oiling the rifle may
be stored indefinitely in a reasonably dry place without
fear of any deterioration of the bore.
V. True metallic fouling consists of a thin film of
cupro nickel, which is abraded from the bullet jacket
and deposited on the bore. Contrary to the usual idea,
TARGET RANGE POCKET BOOK. 5
it has been found that this film does not affect the
accuracy of the rifle and is in no way detrimental.
On the contrary, it is if anything, beneficial, inasmuch
as it offsets the erosion to a minute degree. The thick-
ness of this fouling after several thousand rounds is
less than ".0001. The stripping of a considerable por-
tion of the jacket in the bore is not properly called
metallic fouling, but is a metallic obstruction, which
should be removed by the bullet-jacket extractor de-
scribed in Form 1923, if practicable, or if not, the rifle
should be turned in to an armory or ordnance depot.
VI. The table on page 57 of the Description and
Kules for the Management of the U. S. Magazine Rifle,
Model of 1903, .30 caliber, shows three columns or sets
of deviations of the bullet. The first column shows
the path of the bullet as projected on a horizontal
plane when firing with the line of sight coincident
with a vertical plane through the axis of the bore. In
this column the deviation is to the left up to 500 yards.
This is due to the lateral jump or whip of the barrel.
The second column shows the amount of deviation cor-
rected for by the inclination of the drift slot in the
rear sight leaf. The third column is the difference
between the first and second, shows how the rifle shoots
with the model of 1905 sight, or the amount of drift
which is not automatically corrected.
The following table shows how the average rifle shoots
when issued to the service:
Example: Under standard conditions, with the sight
set at 800 yards, zero deflection, and aiming at the
center of a target 800 yards away, the bullet will strike
1.9" to the right of the point aimed at.
TARGET RANGE POCKET BOOK.
TABLE I (Drift).
Range.
Deviations.
Deviations.
Left.
Right.
Left.
Right.
Yards.
100
200
300
400
500
600
700
800
900
1,000
Inches.
.0
.0
.0
.0
.0
Inches.
.0
.0
.6
1.9
4.0
6.7
Inches.
Inches.
VII. Deviations due to wind are computed by the
formula:
S = (t-~hc Wsinfl
in which
5 = deviation at target in inches.
t = time of flight for range considered.
R = range in yards.
V = muzzle velocity in feet per second.
C = a constant = 10.44.
W = velocity of wind in feet per second.
6 = inclination of the direction of the wind to tra-
jectory.
TARGET EANGE POCKET BOOK.
It may be noted that the wind effect is less for the
model of 1906 ammunition than for the model of 1903
ammunition, formerly used with the U. S. magazine
rifle, model of 1903. This is largely due to the shorter
times of flight which obtain with the former. The de-
viations for the model of 1906 cartridge are tabulated
in Table II below for a 1-mile-an-hour III or IX o'clock
wind.
Table II (Wind).
Range.
Deviation.
Deviation.
Yards.
100
Inches.
0.1
Inches.
200
.3
300
.8
400
1.5
500
2.4
600
3.6
700
5.1
800
6.9
900
9.1
1,000
11.5
VIII. The rear end of the movable base of the model
of 1905 sight bears graduations, the value of the small-
est graduation being about 3.99 inches at 100 yards.
These smallest graduations are known as "points" of
deflection or windage. The following table shows the
TARGET RANGE POCKET BOOK.
lateral correction caused at the target by setting off one
point of deflection:
Table III (Deflection).
Range.
Correction
at target.
Correction
at target.
Yards.
100
Inch(s.*
4
Inches.
200
8
300
12
400
16
500
20
600
24
700
28
800
32
900
36
1,000
40
*An exact point of windage, as stated above, is equivalent to about
3". 99 at 100 yards, but no appreciable error is made up to 1,000 yards
by considering the point equal to 4 inches, and calculation is sim-
plified thereby.
IX. When firing at a given range, if the rear sight
slide is raised by an amount corresponding to 25 yards
of range, the point of impact of the bullet at the target
is raised by a certain number of inches. The follow-
ing table shows how much the point of impact is raised
or lowered by a change of 25 yards in the sight setting.
TARGET RANGE POCKET BOOK.
TABLE IV (Elevation).
Range.
Correc-
tion at
target.
Correc-
tion at
target.
Yards.
100
Inches.
0.7
Inches.
200
1.6
300
2.8
400
4.3
500
6.2
600
8.6
700
11.6
800
15.4
900
19.9
1,000
25.1
X. Table II, page 7, of this pamphlet shows how
much the bullet is deflected by a 1-mile-an-hour wind
blowing directly across the range from III or IX
o'clock. If the same wind blows from the II, IV, VIII,
or X o'clock directions, the resulting deflection of the
bullet is less than when the wind blows directly across
the range, and to obtain these deflections the deflections
in Table II are multiplied by the cosine of 30 degrees,
or .866+ . Similarly if the same wind blows from the
I, V, VII, or XI o'clock directions the resulting de-
flection is still less, and to obtain these deflections the
deflections in Table II are multiplied by the cosine
of 60 degrees, or .5. In other words, a 1-mile-an-hour
wind blowing from I, V, VII, or XI o'clock directions
10
TARGET RANGE POCKET BOOK.
has just half the deflecting power of the same wind
blowing from the III or IX o'clock directions.
To counteract or compensate for wind deflection a
certain number of points of deflection must be set off
on the rear sight. The following table shows how
many points must be used at the various ranges for a
10-mile-an-hour wind from each of the various direc-
tions.
Since the deflecting power of a wind is directly pro-
portional to its velocity, the proper corrections for any
velocity of wind may be readily computed from the
following table:
TABLE V (Wind, Lateral).
Points of windage necessary to correct a 10-mile-an-hour wind.
Range.
III or IX.
ii, rv,
VIII, or
X.
I, V,
VII, or
XI.
in or IX.
II, IV,
VIII, or
X.
I,V,
VII, or
XI.
Yards.
100
Points.
0.2
Points.
0.2
Points.
0.1
Points.
Points.
Points.
200
.4
.4
.2
300
.7
.6
.3
400
.9
.8
.5
500
1.2
1.0
.6
600
1.5
1.3
.7
700
1.8
1.6
.9
800
2.2
1.9
1.1
900
2.5
2.2
1.3
1,000
2.8
2.4
1.4
TARGET EANGE POCKET BOOK. 11
XI. Winds blowing from the XII and VI o'clock
directions have no deflecting influence on the flight of
the bullet ; but these winds have the effect of shortening
(in the case of XII o'clock winds) or lengthening the
range (in the case of VI o'clock winds). Or, to put it
in another way, a wind blowing directly down the range
from the firing point toward the target, has the effect
of raising the point where the bullet strikes the target.
Similarly, a wind blowing directly up the range toward
the firing point has the effect of lowering the point
where the bullet strikes the target.
The following table, showing the effects of these
winds, has been computed, using Colonel Ingall's for-
mula:
AX = C{S(vWp)-S(VWp)}-(XTWp)
and the approximate relation :
Ay = AX tan o>
The following table shows effects of XII and VI
o'clock winds blowing 10 miles per hour. For other
wind velocities, the corrections may be readily com-
puted without appreciable error by assuming that these
corrections are directly proportional to the wind veloci-
ties. The longitudinal wind effects of I and II o'clock
winds may be found by multiplying the figures in the
table by .866 and .5, respectively.
12
TARGET RANGE POCKET BOOK.
TABLE VI (Wind, Longitudinal).
Corrections for 10-mile-an-hour wind.
Range.
VI
yards over
at target.
XII
yards
short at
target.
VI
inches
above at
target.
XII
inches
below at
target.
Yards.
100
1.0
0.9
.03
.02
200
2.0
2.0
.12
.11
300
400
3.2
4.5
3.2
4.4
.41
.69
.40
.68
500
6.1 6.0
1.4
1.3
600
8.0 8.0 2.5
2.4
700
10.2
9.9 4.4
4.3
800
13.6 13.3
7.8
7.6
900
19.9 19.0 14.7
14.1
1,000
26.7 25.5 25.1
23.9
NOTE. The correction in sight elevation in yards correspond-
ing to inches above or below may be read from the second or
third columns of this table.
XII. The following diagrams illustrate graphically
the values of the point of deflection and of the elevation
corrections on the several standard targets at the several
ranges prescribed in Small-Arms Firing Regulations,
1906.
TARGET RANGE POCKET BOOK. 13
Plate I simply illustrates how the value of any cor-
rection on the sight increases with the range.
Plate II shows the value of the point of deflection
on the ;; A' 7 target at a range of 200 yards. This dia-
gram also shows the value at the target of a change of
sight setting of 50 yards.
To illustrate the method of using this and the sub-
sequent diagrams, let it be supposed that a shot was
fired at the "A" target at a range of 200 yards and
that the bullet struck at the point marked "P" (Plate
II) , then the correction necessary to bring the next shot
on the center of the bulPs-eye may be read directly from
the diagram, thus: 75 yards less elevation and 2 points
of deflection to the left.
WAR DEPARTMENT,
OFFICE OF THE CHIEF OF ORDNANCE,
Washington, April 28, 1908.
FORM No. 1998.
Ed. June 13-17-5,000.
26791 O 1587.
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Correction corresponding to a change of elevation of 25 yards.
Correction corresponding to a change of elevation of 25 yards.
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