The conduct of fire : fire for adjustment

Fire for adjustment (пристрелка - tir de réglage). Fire for adjustment has for principal object the determination or verification of the firing data. Observing the fire, the battery commander determines the proper data that should be set off on the sights, quadrants and fuze setters in order to cause the projectiles to strike the target. The first data ordered with approximate methods are usually incorrect. By observing the errors in the fire, and by constantly changing deflection, range and rate of burning of the fuze in accordance with the observed errors, settings is finally found, which will cause the fire to produce the greatest effect upon the target.

The adjustment includes three operations, that in principle are carried on simultaneously were :

– the adjustment in direction is aimed to bring the sheaf of fire to bear on the desired front of target and to introduce the correct modifications of deflection setting due to the resistance of the air and to rotating movement of the oblong projectiles of rifled guns;

– the adjustment in range determines or verifies the range by bracketing; that is, by inclosing the target between rounds which, fires at a known difference of range, hit, respectively, in front of and behind the target;

– the adjustment in height of burst, in the case of time-fuze fire, is effected in order to determine the proper corrector to obtain the normal height of burst in fire for effect.

Usually the adjustment is done immediately before the beginning of the combat, but artillery in position can register its fire upon positions where an enemy is known to be or where he is expected to appear, determining the fire data for reaching certain prominent features of the terrain, such as crests, plainly marked trees, houses, etc. In such a way it gaines the ability to open immediately effective fire upon a target appearing at or near them.

Fire for adjustment can be done :

– by piece : either all the guns are used, firing in succession from a flank of the battery to the other, or a single gun is designated for the purpose. It is usually employed in percussion fire, or when the rounds are few;

– by platoon : all the guns of the battery are ready for fire, the first platoon loaded with shrapnel. At the sign of the commander of the battery, the two guns of the first platoon fire at the same elevation with a pause of two to three seconds. After the correction of the range and of the deflection, the second platoon fires at its turn; then they fired alternating, until the range is correctly determined. The bracket is 200 m and the guns sight among them;

– by battery : the determination of the range is obtained by battery series (one round every 3’). The bracket is the same as for the adjustment by platoon. It is usually employed when the target was well observed and the guns are defiladed alike.

Either time or percussion fire can be employed, but usually fire for adjustment is done with the same kind of projectile to be used to fire for effect, and it is employed in the same way (non delayed-action H. E. shell, delayed-action H. E. shell, time shell, time shrapnel, and percussion shrapnel). However, when fire for effect will be with impact fuze, but the ground around the target is such that the shells cannot act reliably on impact (swampland, lakes, river) or, even if effective, cannot be observed (brushwood, corn, deep snow, meadows, ditches), the adjustment is done on time. Adjustment with time fire is simpler, being independent of the nature of the ground and the shape of the place, and quicker, since at the same time it adjusts also the height of burst of the shrapnel.

With the new direction, fire for adjustment is reduced in order to pass as quickly as possible to fire for effect. To accelerate the adjustment, the battery at first fire at a chosen point in the area of the target, in order to determine the elevation and correct the height of burst of the shrapnel. As soon as the target is clearly located, the guns adjusted their fire until they obtain the 200 m bracket. Fire for effect with time shrapnel begins at the middle of the 200 m bracket, usually with a group of control rounds at low burst from all the guns of the battery, in order to verify the elevation, the height of burst and the distribution of fire. If necessary, a correction of 25-30 m may be done, according with the observation of the fire.

Firing at single range against uncovered animated target the 100 m bracket must be adopted, against shielded artillery or animated targets under cover it must be lowered to 50 m. When the terrain near the target does not permit to obtain the low bracket, the high bracket is lowered by battery series, going back of 25-50 m. Then the guns shell the whole area, using progressive fire (at will or at command, according with the range). Against shielded guns the bracket is always at 50 m. If the target is on a slope with a gradient of 3-4 millièmes, the correction is changed of 2 millièmes accordingly, and the area is shelled.

When the rounds are seen falling on the target or some of them are short and some long, there is no bracketing : the guns adopt immediately the elevation observed and fire for effect began, after having firing the group of control rounds. Against animate targets at a distance of less than 1000 m, there is no adjustment, but the distance is verified with a battery series.

Adjustment with time fire (пристрелка на време). It is usually done with low fuzed shot (set on average at about 1/1000 of the distance), since they are better observable. Indications about the trajectory are given only by short shots, shots on the graze and the fall of the bullets.

The adjustment is done by series of two shots, given in turn by the two platoons, by the same platoon, or by the same gun, with an interval of 2’-3’. With quick-firing guns, when the target is well observed and the guns are equally defilated, the adjustment is done by series of four shots, given by the whole battery and distributed along the entire front of the target. If the ammunition is low, the adjustment can be done with a single shot, possibly with impact fuze. With not quick-firing guns, the series of two guns are done in turn by all platoons.

The determination of the distances of the bursts to the target can be done only when the area around the target is flat and with a slope facing the firing battery, or even if it is level, but it is lower than the firing battery. The estimation of heights of the bursts, when trajectories are distant from the target and pass higher or lower than it, should be done in relation not to the target, but to the area over which they occur.

The height of burst is regarded as correct when the bursts are:

– all or more than ½ low;

– ½ low and ½ on graze;

– ½ low and ½ normal;

– ½ on graze and ½ normal and high;

– all good, but the fall of the bullets is certainly observed and makes it possible to draw a conclusion about the position of the trajectories.

The fuze set must be changed when the burst are :

– all or more than ½ on graze;

– all or more than ½ high;

– all good, but the bullets were not observed.

Adjustment with percussion fire (пристрелка на удар). With quick-firing guns, it is done with percussion shrapnel, firing by gun until the 200 m bracket is obtained, and by platoon to obtain the low bracket (50 m), then a group of 8 shots was fired at the middle of the low bracket.

At that point the adjustment goes on as follows :

1) when the height of the target is one possible deviation :

– if 2-4 shots are short, no correction is introduced, and the fire for effect begins;

– if only 1 shot is short or all the shots are long, the fire is moved to the short limit of the low bracket;

– if 5-6 shots are short, the level is raised by 1;

– if more than 6 shots are short, the fire is moved to the short limit of the high bracket.

2) when the height of the target is greater than one possible deviation :

– if 2-3 shots are short, no correction is introduced, and the fire for effect begins;

– if only 1 shot is short or all the shots are long, the fire is moved to the short limit of the low bracket, and the level is raised by 1;

– if 4-5 shots are short, aiming is done on the level;

– if more than 5 shots are short, the fire is moved to the short limit of the high bracket.

If the falls of at least 6 shots of the group are not seen, more shots are fired until 6 observations are reached.

page 1

page 2

page 3

page 4