It is often suggested that a thumb-stall which stands up and blocks the
fore sight from the left eye is an assistance to right-shouldered
shooters, and sometimes it is. But as it has no effect on the manner of
bringing up the weapon, it must require revision to get the correct aim
if the weapon is not brought up correctly. The author thinks that a long
course of shutting the left eye will _force_ the right eye into becoming
governing eye by habit. Some people have neither eye greatly the
governor, so that each has an influence on the manner of the “present,”
and helps to fix the point the gun is brought up to. This point may be
half-way between the extended lines from the two eyes to the foresight,
and permits of no real alignment until the gun is moved after
presentation, which is always slow. For such men nothing but shutting
one eye will be of much use, but for those who have a controlling left
eye it is different, and a cross-eyed stock, or shooting from the left
shoulder, is to be recommended. Those who have a control eye need not
necessarily be able to see the game with it. Provided they see the
latter with one eye and take alignment of the breech and fore sight with
the control eye, that is enough. If the eyes are pairs—that is, not
crossed—and produce on the brain but one image of an object focused,
then the direction of the alignment over or upon the game or target is
accomplished in the brain, and the hands obey. That is to say, the left
eye may be unable to see the sights, and the right eye may be unable to
see the game, but as the images on both are superimposed on the brain
the aim is quite correct for normal eyes. A beginner thinks this
impossible, but if he uses a thumb-stall, and blocks the fore sight from
the left eye, and puts a card over the muzzle, so as to block the right
eye from seeing the target, and then focuses the latter, and not the
fore sight, he will soon become unconscious that he is blocking out
anything from either eye.
As the ability of the eyes has had to be referred to here, it may be
well to remark that any normal eyes can see the shot in flight against
the sky, and this ability has been used to advantage in coaching
shooters. To see this phenomenon, stand slightly behind the shooter, and
look for a little darkening of the sky in the direction of the aim; it
will be easily seen about the time the shot has spread to a foot, or so,
diameter. Whether anyone can see the shot much nearer than 15 yards or
farther away than 20 yards is questionable; the spread of the pellets
reduces the dark shade-like appearance, and it vanishes. Consequently,
experts who see clay birds apparently in the middle of the pellets may
be quite correct at short distances, and appearances may be absolutely
wrong for game or clay targets at distances farther away than the shot
can be detected. The bird may have flown another two yards by the time
the shot intersects its line of flight. Consequently, this ability of
the coach to see the shot should only be relied upon at about 20 yards
range.