There are two kinds of ballistics, one is interior ballistics and the other is exterior ballistics.

Internal ballistics discusses various physical phenomena after ammunition is fired and before the warhead leaves the muzzle. Among them, the important ones are:

1. bore pressure: the charge expands when burning, because the warhead is blocked in the front and the mechanical lock is blocked in the back, which will produce great pressure in the bore, generally speaking, it is between tens of thousands of pounds/inch and hundreds of thousands of pounds/inch. This pressure is the main force to push the warhead to separate from the shell. Of course, the greater the force, the better, because the faster the warhead flies, the less it is affected by gravity within a fixed distance. But if it is not within the proper range, it will also cause danger.

2. Double track into orbit: Double track into orbit makes the warhead rotate and make the warhead fly stably. However, the number of double-track in orbit has a very important relationship with the speed of orbit (speed refers to the length of 360-degree rotation of double-track in orbit) and the weight of warhead. The correct warhead will have better accuracy if it is used in the right loop. For example, for a.223 caliber gun, a 55 gr warhead is suitable for a circle over 12 inch. If it is a 9-inch circle, it is best to use a warhead above 69 gr

Barrel hardness: When the warhead passes through the barrel, the barrel will swing up and down like a whip. The amplitude of the movement will affect the position of the warhead exit. At the same time, the barrel will heat up, and the metal will expand due to the heat, which will affect the tightness of the warhead and the multi-wire. To solve this problem, it is generally to increase the thickness of the barrel. Because increasing thickness can increase hardness and slow down temperature rise.

External ballistics mainly discusses various factors that affect the flight of a warhead after it is exported.

Anything on the earth will be affected by gravity. In fact, light is also influenced by gravity, but whether light is a wave or a particle is still inconclusive. As soon as the warhead came out of the muzzle, the acceleration stopped. Gravity will pull the warhead to the ground. So the flight path of any warhead is curved. If the barrel is parallel to the ground, the warhead will never touch any point on the extension line of the barrel. Therefore, the bucket is slightly upward.

Trajectory and line of sight diagram

The curvature of this arc depends on the initial velocity and the coefficient of the bullet. The initial velocity is large, the warhead is at the same time, the flight distance is long, the gravity action time is short, the influence on the arc is small, and the flying arc is relatively flat. A flat trajectory means that the warhead will not deviate too far from the line of sight, which is much easier for the shooter. Basically, you just aim at it and hit it there. You don't have to worry about adjusting the alignment or adjusting the aiming point.

I believe everyone has heard of the word return to zero, mainly because of the relative relationship between trajectory and line of sight. One is a straight line, the other is an arc, and there are only two intersections at most. How to get close to the intersection depends on the purpose of the gun. A gun with an optical sight, if it has an adjustment button, basically moves the diplomatic point so that the warhead can accurately hit the aiming point. Military rifles, because there will be no time to adjust the scale in battle. Most intersections are fixed. For example, AK-47, the standard operating procedure is to set the gauge at 200 meters, and then shoot at the target of 25 meters. At this point, you can adjust the top, bottom, left and right sides of the ruler. When the warhead hits the bull's-eye, it completes the battle to zero. At this time, the gun, from zero to 300 meters, can hit the aiming point within nine inches. For infantry, this accuracy is enough. Think about it. An adult man's upper body is about eighteen inches and ten inches wide.

Stern warhead

The relationship between warhead coefficient and trajectory is mainly because the warhead must fly in the air, and the air resistance will affect the flight speed of the warhead and the trajectory. Generally speaking, the coefficient of streamlined warheads is relatively high. Under the influence of wind, the stern warhead is unlikely to deviate from the line of sight or lose too much speed. There is also the need to adjust when the shooter aims up and down. This is all in pursuit of higher goals. Here is a simple formula.

30-degree angle (both up and down):

Distance X 0.7

45 degree angle

Distance X 0.9

For example, there is a target on a hillside 600 yards away. The shooter must shoot at an elevation of 30 degrees upward. After calculation, it is 600X0.7=420. The shooter should adjust the scale or sight like shooting a 420-yard target. This is only an estimate, not absolutely accurate.

If you are interested, you can buy a chronograph to measure the exit speed of the warhead, and some ballistic software can draw the theoretical value of the trajectory. This is a good reference and can help the shooting accuracy.