Rock Island Argus. (Rock Island, Ill.) 1893-1920, 1912-11-04
SPEED OF A SHOT
Finding the Velocity of a Missile
a Simple Matter.

Persons at all interested in gun firing
Of any kind, whether of the revolver
or rife or Of heavy ordnance of any
kind, occasionally come upon the term
''muzzle velocity" and velocities of the
missile at stated distances.
How can anybody tell how fast a
bullet is travelling when it leaves the
muzzle of a weapon is a likely COM
ment on the part of the layman.
AS matter of fact this approximate
velocity of the missile may be one of
the easiest Of determinations to make
| In the first place. a drumlike cylinder
is made of fixed diameter and of suf-
| fciently stiff paper to allow of its re-
volving rapidly on a spindle. Using a
/ cylinder of small circumference, it is
necessary that the speed approach
1000 revolutions minute. These rev.
olutions are produced by electric pow
/ er, and the count is made by an exact
mechanical register.
The gun is placed securely at the re-
| quired distance from the drum and is
sighted directly at the center of the
cylinder, which is spinning at so
many rods, even miles, a minute, as
! its circumference determines. With
the drums speed adjusted an electric
current discharges the weapon, the
bullet striking the center of the drum
as measured from top to bottom.
| The reader understands that with the
drum stationary the bullet would pass
directly through it on the line of its
diameter, coming out on the other side
with scarcely a shade of impeachment
With the drums periphery whirling at
the rate of 1000 revolutions minute
and its diameter only fraction more
| than a foot this would mean a rate of
1000 yards in sixty seconds. Thus in
the fragment of a second necessary for
| the bullet to enter one side of the pa
| per drum, cross it and out at the other
side the opposite side of the drum
would show considerable deviation
from an exact diameter of line of pas
! sage.
| 1t is this space of detection shown
| inside the further rim of the drum that
is used for the computation of velocity
of the missile. The speed Of the cylin-
der may be computed to the ten thou
sandth part of a second if necessary
and the lineal distance run in that time
be charted in perpendicular lines on
the inner side of the paper. At what
ever line the bullet penetrates outward
1t registers its time in crossing the
! diameter Of the cylinder. If it has re-
| quired the ten-thousandth part of a
second for the bullet to fly one foot its
muZzle velocity TO the mile may be
computed by any schoOlboy. BY the
same process, too, the bullets velocity
at 100 yards or 500 yards may be de-
| termined.
Years ago before wing shooting had
become an art the farmer with his
muZZle loading shotgun and charge of
Black powder would shoot directly at a
wild goose or duck in full flight He
evolved a theory of his own as to the
oncoming bird, holding that the heavy
breast feathers turned" the shot. He
waited until the bird had passed him
when, firing directly at it, he could
bring down his quarry.
But IT was not because the bird was
not vulnerable, coming breast on
The fact was that it eflw over his
/ charge of shot. BEFORE he could pull
the trigger and the hammer fell on
the percussion cap and the compare
lively slow black powder could be ig-
| nited and exploded, sending the shot
twenty-five or thirty yards, the bird
had flown yards perhaps beyond its
position when the fowler first touched
the trigger. But firing directly at the
bird after it had passed the shot
/ charge had a strong tendency to drop
as II flew, and the bird flying on Il
level line got in the way" of the
charge.
Today the modern nitro powders are
Immensely quicker than WAS the old
black gunpowder, yet it has been an
engineering problem to determine just
how fast and in what line a charge Of
shot will travel. In this deteTminl-
ton the revolving drum device has
shown several important facts which
have been taken in connection with
the speed of individual game birds
and the effects of windage on a shot
charge
That most important fact az to the
dtght Of shot from a modern shotgun
is that at forty yards the shot are
"strung OUT for approximately fifteen
feet. While the leading pellets in the
string have greatest velocity and kill
ing power, at this distance even the
trailing pellets are of sufficient force
to kill.
All this has led TO the modern prac-
tice of the fowler to reckon with the
speed Of his shot, the speed Of the
bird. the influence OF the wind in
drifting" the charge, and out of
these established facts TO lead" the
bird sufficiently to kill It rather than
main and cripple it.-Marvin Holton
in Chicago Tribune.