Direction for firing in fortress-siege
artillery
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Fire for adjustment (пристрелка). The direction emphasizes
that the adjustment must be accurate, but also as fast as possible, in order
to open the fire for effect before the enemy. The
adjustment is usually made with
percussion shell without measuring the deflection of the projectiles. It
is aimed at finding the most probable elevation by : a)
capturing the target in the high bracket, b)
narrowing it by halving until the short bracket was
obtained, c)
confirming the limits of the short bracket, d)
firing a group of shots carried out with the same
data. The
short bracket is fixed at 4-8 deviations or, with bar sight graduated in meters, at 100 m. The high
bracket is determined by increasing the short bracket by 2, 4, 8… times,
according with the probable error in determining the distance. If already, the
first shot is very short or very long or close to the target, then a high
bracket wider or smaller than assumed can be taken. In narrowing the range, if a
sure shot is obtained on the target, at this elevation two observation are
made : –
if they are different (on straddle) shooting continues
at the same elevation to execute the group; –
if both the shots are seen on the same side, the distance
is increased or decreased by a short bracket; –
if the bracket is not obtained, the high bracket is
further narrowed or a new bracket is sought. If the observation is
difficult, the adjustment is made by salvos with the high bracket. The
limits of the short brackets must be repeated to determine the elevation,
starting at the final limit. If
the second observation of the limits of the short bracket is : 1)
the same as the first (– – or + +), the limit is
regarded as confirmed; 2)
opposite to the first, i.e. on straddle (+ – or –
+), 2 or 4 observation more are made : a)
if the two following observations are on straddle (–
+ – + or + – – +), the elevation is maintained and two more rounds are fired
: if the group is satisfactory, the fire continued at the same elevation; b)
if the two following observations are equal to the
last one (– + + + or + – – –), the verified limit is regarded as false, and
the short bracket is sought again; c)
if the two following observations are opposite to
the last one (– + – – or + – + +), two more rounds are fired to obtain the
group : if the ratio of short to high shots is satisfactory, the elevation is
accepted, but if only one shot of the group is opposite to the others (– + –
– – – or + – + + + +), it is necessary to pass to the other limit, if it has
not been verified, or move to the centre, it has been verified. After
the most probable elevation has been found, if any of the guns gives 3-4 equal
observations, its elevation is changed by a short bracket and its adjustment
is made separately according to the general rules. If
the fire is resumed after a few hours of interruption, the short bracket must
be checked and if it turns out to be false, the elevation must be changed by
a double width of the short bracket and the adjustment continues according
with the general rules. If
the number of shrapnel with T&P fuze is great, the adjustment can be made
with percussion shrapnel, firing
by battery or platoon salvos to speed up the whole operation. At
first the adjustment is made with shell, exactly as above, but after having
obtained the short bracket : a)
at distances up to 2500 m against targets in the
open, the whole battery shifts to fire for effect, using time fuzes and
firing in series (съ
батарейни
редове), aiming to the centre of the
short bracket : according with the observations obtained from the first
series, if necessary, the elevation and the bursting time of the fuze are
corrected; b)
at ranges over 2500 m or against covered or
partially covered targets and generally with mortars and short guns firing
with time fuze, the limits of the short bracket are repeated, then the
battery shifts to fire for effect, using time fuze and aiming to the centre
of the bracket, if the two limits has been confirmed, or at one of the
limits, if a shot on straddle has been obtained. In
the first case, the time of burst of the fuze is set immediately, in the
second case it is set by identifying the most probable elevation. If the
correspondence between the fuze and the elevation is not known, a platoon for
the four-gun battery or two platoons for the six-gun battery switchs to time
fire, while the percussion fire goes on at the same elevation of the time
fire, until the correspondence is found, then the whole battery switchs to
fire for effect with time fuze. To
set the fuze two rounds fired in succession must observed : a)
if they are very high or high, the fuze is
lengthened by 0.8, 0.4 or 0.2 seconds, depending on the evaluation of the
height of the bursts; b)
if two burst on graze are obtained, the fuze is
shortened by 0.8 seconds and in any case not less than 4 probable deviations
of the shrapnel in height (the probable deviation of the shrapnel in height is
regarded as corresponding with the triple that of the shell height); c)
if one is high and one on graze, two more rounds are
fired at the same elevation and with the same fuze, and if two low bursts are
obtained, the fuze is shortened to obtain the required average height of
burst. Time
fire is regarded as good when out of 6 shots no more than 1 bursts behind the
target and if the average interval does not exceed 4 probable deviations of
the shrapnel (about 100 m). The burst height is regarded satisfactory when of
6 shots 1 bursts very low or hits the ground. Control
rounds must be fired whenever there is any doubt as to the accuracy of the
burst or their effect, firing two rounds or a full battery series (4-6
shots). They are fired at an elevation increased by 2 short brackets and the corresponding
fuze lengthened for low bursts. Also in this case if a cannon gives different
bursts from those of the others (all high or on graze), its elevation is
corrected by a short bracket. If
there are not percussion shells or the target is placed where the observation
is difficult (marshy land, with ravines, covered with tall and dense plants),
the adjustment can be made with time
shrapnel, firing by platoons with fuze set for low bursts. The short
bracket is restricted up to 8 probable deviations, when their limits are
confirmed, the fire is moved to the centre of bracket and the guns shifts to
fire for effect by battery series. The
adjustment in direction is made
starting with the deflection reported in the firing tables and taking into
account the slope of the axis of the guns and the direction and power of the
wind. With the start of the group, the direction of each cannon is checked
individually. The adjustment is regarded as complete when out of 6 rounds,
fired with the same lateral deviation, 2-4 rounds fall in the same part of
the target. The
distribution of fire is
carried out by gun or by platoon,
according with the features and the size of the target, and after having
repeated the short bracket, in order to obtain the distribution of the shells
over the entire width of the target. Whit short target fire must be always
concentrated. The
switch of fire must be always done
to a closer target. If it is caused by the unexpected appearance of a danger
a short distance from the battery, it takes place without a specific order
from the superiors; otherwise, it can be carried out only according with an
order. If
the battery is firing with shells or with shrapnel with percussion fuze, the
fire is directed at a new target, giving the elevation corresponding to the
distance and framing the target in 4-2 short brackets, then switching to time
fire for effect at the small limit by rapid fire in succession. If
the battery is firing with time shrapnel, at first the guns shoot quickly at
the old target, then they are loaded with shells or shrapnel with percussion
fuzes and finally they switches the fire as above. If
the battery is firing with time shrapnel and the new target is near the old
one, the elevation is reduced for percussion or low bursts fire to obtain
indications about the distance to the new target, then the battery switches
to fire for effect. The
direction gives also detailed information about the adjustment and fire with
percussion shell measuring the deflection of the projectiles, and with time
shrapnel measuring the interval and the height of burst. |