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The main factors affecting the shotting
Jan 12, 2018

In the constant external conditions, the same shooter repeatedly shot several times, even though the weapons, ammunition, aiming point are the same, the bomb points are not coincidental, but showing a seemingly disorganized distribution. This phenomenon is called ballistic natural distribution. It is precisely because of the existence of natural distribution, so Sagittarius level no matter how superb aiming shooting without any error, but as long as a little distance, the bullet can never hit the same point forever (why say Distance "? If you put the gun on the target, continuous hit a point is not too hard).


As a typical example of projectile dispersion, we can see that half of the centers are dense and half of the periphery are relatively loose

Therefore, a sharpshooter, even if he aiming at shooting without any mistakes, only allows the projectile control in a range, and the farther the distance, the greater the range. So suppose a gun with some kind of bomb, the natural spread in the distance of 100 meters is a circle of 1cm in diameter, in the distance of 500 meters is 5cm, in the distance of 1000 meters is 10cm; a god shooter in the absence of mistakes, In the distance of 100 meters to ensure that playing Kung Fu tea with a small cup, but in the distance of 500 meters can only be guaranteed to play ordinary meals with ordinary rice bowl, and in the distance of 1000 meters can only guarantee hit the soup bowl. However, as the distance increases and the spread of the surface can not be calculated using the trigonometric function, in fact, it is a trumpet. For example, it is 1cm scattered at 100m, 6cm at 500m, and maybe 20cm at 1000m. In short, the longer the distance, the greater the spread. If you want to use a sniper rifle that can only hit a ping-pong racket at 100 meters to hit a toothpick at a distance of 500 meters, there is no grammatical error if you say "can hit", but if you say " "That is bragging.


A trajectory in Earth's atmosphere is determined by the three ballistic elements of muzzle velocity, launch angle and ballistic coefficient. Therefore, when we exclude the human factor (the level of the archer) and the environmental factors (wind, temperature and pressure conditions ), All the factors that affect the initial velocity, launch angle and ballistic coefficient will affect the size of the natural dispersion. These factors are all focused on the slight differences between guns and ammunition. Although these differences may be reduced by selecting high-precision guns and ammunition, thereby reducing the impact of these negative factors, reducing the natural dispersion and increasing the hit rate, they can not be completely eliminated (Which is just as true as the physics of junior high school, "there is no absolute round in the world"). Therefore, although the shooter can grasp the law of spreading the surface, it can not grasp where the bullet will hit the surface.

Well, let's talk about the factors related to bombs. Although the shooters are the same person and the guns can be the same one, the bullets fired can not be the same. Therefore, the factors involved in bombs can all be summed up as one "consistency "The problem. Let me remind everyone once again that there is no absolute consistency. The so-called match-bombs and precision bombs are actually closer in terms of "consistency" than ordinary bullets. Here are the main:

1. Ignition pressure: ignition of the bottom of the fire dose, pressure medicine density will affect the instant firing firing pressure, thus affecting the consistency of the muzzle velocity.

Charges: Each shot can not be absolutely the same dose, regardless of the difference between 0.1 mg or 0.001 mg will lead to differences in the size of the thrust, thus affecting the consistency of the initial velocity.

3 pull stretch: This depends on the time of assembly of the cartridge into the depth and the cartridge shell mouth and bullet cylinder central part of the tight mouth force, so bullet shell size and shell mouth of the weak difference and the depth of the weak difference will lead to the muzzle velocity different.

4. Drug temperature: temperature changes will affect the firing rate of propellant changes in the chamber pressure and muzzle velocity of consistency. By the same token, the barrel temperature at the time of shooting also affects the muzzle velocity, so the muzzle velocity of the cold barrel and the hot barrel is also different. This is why most of the precision tests of sniper rifles hit a set of 3, while the accuracy test of assault rifles mostly hit 10 or 10 rounds of the above reasons.

5. Pharmacy volume: This refers to the bullet shells loaded into the shell, the total volume of the space after the bomb, the size of the chamber volume affect the packing density, packing density and also affects the speed of combustion, thus affecting the consistency of the muzzle velocity, and Bullet shell size tolerance and warhead loading depth has an impact on the chamber volume.

6. The state of charge: refers to the firing of projectile firing projectile, the propellant in the shell distribution. Because there is free space in the cartridge, the propellant does not completely fill the cartridge. Therefore, the charge varies due to the various actions performed by the shooter when it is fired and the movement of the propellant charge For example, concentrate on the bottom of the shell, sometimes on the bottom of the warhead, and sometimes evenly on the underside of the shell. These different distributions will cause ignition, inconsistencies in combustion conditions, thus affecting the consistency of muzzle velocity.

7. Coherence of propellant burning: inconsistencies in the size of the pellets, in particular due to inconsistencies in the particle size of the propellant, due to the unevenness of the propellant composition or the shape of the pellets, in particular inconsistencies in the thickness of the combustion layer, lead to inconsistencies in combustion and hence to the consistency of the muzzle velocity.

8. Warhead weight: Even with exactly the same thrust, a slight difference in warhead weight results in a difference in muzzle velocity. In addition, during the flight, the weight difference of the warhead will also lead to the environment (such as the wind) on the warhead size of the difference. (So the sniper ammunition, the ammunition are mostly heavy warheads, and long-range sniper attacks often use heavier large-caliber rifles, which can reduce the impact of wind side)

9 bullet centroid position: different positions of the center of mass, will cause the flight attitude, rotation and defense against the wind different, these will cause the ballistic coefficient changes. Why most of the game bomb using pure lead bullet core, it is because the simpler the structure easier to maintain the consistency of the position of the center of gravity. If you use composite core, because there are several components, the consistency of the position of the center of mass will inevitably be a little bit worse.

10. Warhead aerodynamic shape: Of course, in front of not say there is no absolute pure it? Even with the same mold will have a very slight difference in the air when flying, the geometric size of the standard will cause the drag coefficient changes.

11. Bullet cross-section density: including weight and diameter, which is also a factor that can affect the ballistic coefficient.

12. Flight attitude: the larger the nutation angle, the greater the impact on the ballistic coefficient.

13. Flight speed: There are many factors related to the flight speed, not detailed here (lazy).


The appearance of the bullet looks symmetrical to the naked eye, and the position of the bullet is also correct, but in fact the shape must be asymmetrical and the bullet must be crooked (please use "there is no absolute round in the world" "Two parallel lines will have a little intersection" These junior high school knowledge to understand)


The simpler structure of the warhead, the center of mass of the more easily consistent


Since the bullet will be crooked, the center of mass of the bullet will not be on the axis of the barrel when it moves in the bore.


Warhead and move precession


The shock resistance in flight, if the warhead's shape is not symmetrical (in fact it must be non-symmetrical, but it is indisputable) can have an effect on the direction of flight


Aerodynamic effect on the warhead, so that the consistency of speed, shape and centroid impact a lot

Through the factors listed above, we will find that in some reports, there are reports that some 88 retarders use the method of "weighing bullets." In fact, they have no practical effect and can only serve as psychological comfort because you can tell But the weight of the whole bullet, when the weight of the two bullets exactly the same (assuming "absolute" is established), but it is also possible that the bullet warhead weigh a little less firing a little less, another bullet in contrast. And we do not forget, there are differences in the weight of the shell there, not to mention the location of the center of gravity, tight mouth and so different, so the bullet is unable to pick out all aspects of the consistency are very close to ammunition.

In addition, in some movies or novels, the legend of defending warheads is also of no real significance. Without precision gauges and equipment, frustration by human eyes and manpower only leads to more and more distortion. Experienced foreign experienced players, play with the hand-loaded projectile through accurate analysis of the balance, bomb, press-fit, tight mouth and grinding and polishing complete sets of processes and equipment to assemble a high degree of consistency of ammunition to. However, they still have to buy high-precision bullet produced by famous brand manufacturers, because the consistency of warhead weight, center of gravity and size still depends on the high-quality products coming out of the production line.

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