Artillery regulations, "is the projectile _par excellence_ ... against
all animate targets which are not under cover." It achieves its purpose,
as has been said, by sending a shower of bullets over an area of ground
in such quantity that this is swept from end to end. These bullets are
propelled, in a cone, forward from the point of burst of the shell, and
the effective depth of this cone at medium ranges with a fairly high
velocity gun may be taken at 300 yds. Further, the corrector enables the
artillery commander to burst his shells at any desired point; for
example, a long fuze may be given, to burst them close up when firing
upon a deep target (such as troops in several lines, one behind the
other), and thereby to obtain the maximum searching effect, or to obtain
direct hits on shielded guns, while a short corrector, bursting the
shell well in front of the enemy, allows the maximum lateral spread of
the bullets, and therefore sweeps the greatest front. The number of
bullets in the shell is such that troops in the open under effective
shrapnel fire must suffer very heavily, and may be almost annihilated.
If the enemy is close behind good cover, the bullets, indeed, pass
harmlessly overhead. This, however, leads to a very important fact, viz.
that artillery can keep down the fire of hostile infantry, "blind" the
enemy, in Langlois' phrase, by _pinning it down_ to cover. Under cover
the men are safe, but if they raise their heads to take careful aim,
they will almost certainly be hit. Their fire under such conditions is
therefore unaimed and wild at the best, and may be wholly ineffective.
_Common_ shell and _high-explosive_ shell (see AMMUNITION) belong to
another class of projectile. The former is now not often used, but a
certain proportion of H.E. shell is carried by the field artillery in
many armies (see table in ORDNANCE: _Field Equipments_). This has a very
violent local effect within a radius of 20 to 25 yds. of the point of
burst (see AMMUNITION, fig. 10). It therefore covers far less ground
than shrapnel, and is naturally used either (a) against troops under
substantial cover or (b) to wreck cover and buildings. In the former
case the shell is supposed to send a rain of splinters vertically
downwards. This it will do, provided the fuze is minutely accurate, and
a burst is thus obtained exactly over the heads of the enemy, but this
is now generally held to be unlikely, and in so far as effect against
_personnel_ is concerned the H.E. shell is not thought to be of much
value. Indeed, in the British and several other services, no H.E. shells
at all are carried by field batteries, reliance being placed upon
percussion shrapnel in attacking localities, buildings, &c., and for
ranging. Experiments have been made towards producing a "H.E. shrapnel,"
which combines the characteristics of both types (see, for a
description, AMMUNITION). For the projectiles used in attacking shielded
guns, see section on "field howitzers" below. _Case shot_ is now rarely
employed. In the war of 1870-71 Prince Kraft von Hohenlohe-Ingelfingen,
who commanded the Prussian Guard artillery, reported the expenditure of
only one round of case, and even that was merely "broken in transport."
The close-quarters projectile of to-day is more usually shrapnel with
the fuze set at zero. Langlois, however, calls case shot "the true
projectile for critical moments, which nothing can replace."