Wikipedia
In field artillery, the accuracy of indirect fire depends on the use of aiming points. In air force terminology the aiming point (or A.P.) refers to holding the intersection of the cross hairs on a bombsight when fixed at a specific target.
An indirect fire aiming point provides a point of angular reference to aim a gun in the required horizontal direction – azimuth. Until the 1980s aiming points were essential for indirect fire artillery. They are also used by mortars and machine guns firing indirectly.
The essential feature of an aiming point is that it is at a sufficient distance from the gun using it. The reason for this is that, while firing, guns, particularly towed guns, move back a short distance – perhaps a foot, as their spades embed and may move more in soft ground. When they traverse their barrels their sights also move because they are not at the point of pivot. All this means that if the aiming point is too close then the angle to the aiming point changes. This aims the guns off-target, possibly up to several hundred meters.
For gun-laying purposes a distance of a few kilometers from gun to aiming point is sufficient. An aiming point would be a sharply defined and easily distinguished feature, such the edge of an obvious building. However, this presents problems in featureless areas, in bad visibility or at night and putting lights on distant aiming points is seldom practical. Therefore, methods of simulating a distant aiming point are required.
Usage examples of "aiming point".
Beak, his gun in his right fist, was aiming point-blank for The Shadow's heart, even before he spied his cloaked opponent.
There was a gap in the gabions he'd picked earlier for his first aiming point.
It was shaped like a horseshoe, a lucky horseshoe, and it made a perfect aiming point.
If its aiming point is on front of the glacis, it'll ricochet off.
Then it ran a rapid series of calculations and adjusted the aiming point appropriately.
On the other hand, if you've got vibration problems, every time you change your aiming point, you add a new variable into your targeting geometry, and that makes things a lot worse.
The white shirt would give his opponent a fair aiming point, he was observing the conventions scrupulously.
The shaft of the pruning hook even provided an aiming point as he trained the pistol at the Colonist's center of mass.
Steadily he increased the pressure, staring hard at his aiming point on the throat, resisting any impulse to jerk the trigger that final hairbreadth.
McLanahan had only to position a set of electronic preselected aiming point on the radar scope, and the bombing computers would do the rest.
Right now he was too busy looking ahead and pinpointing his approach, and computing the distance from the aiming point he’.
January put the dummy gimmick right on the aiming point just as he had so often in the Salton Sea, and Fitch powered the plane down into the violent bank that started their 150-degree turn and flight for safety.
There was a tunnel not far ahead, and diey would be safe there if diey could get past die aiming point where die spotter plane was sending die bombardment.
Reflection from the smooth glass made the empty rectangle a good aiming point, and Kelly's quartering angle on the sedan meant that the bullets would snap across the tonneau and the space most likely to be occupied by the driver's head.
The best you could do was diffuse the cacophony so that it might come from anywhere in a mile radius instead of giving the enemy a sharp aiming point.