Wind deflection formula

2nd floor "rtyqwe 123456? A leader? " 12 "directly copied the teaching material of M24 sniper rifle of the US army.

That formula is derived from a large number of shooting experiments and only applies to M24, not to rifles other than M24.

Arthur. j？ Modern Practical Ballistics written by Pesha (Modern? Practical? Ballistics), reference formula.

Wind deflection is a nonlinear function related to range, wind speed, ballistic coefficient and initial velocity. Define the following variables:

Wi？ - ? The wind is off? Wind? Drift, in inches, 1? Inch = 25.4mm

r？ - ? Distance range, unit code, 1? Yard = 0.9144m; ?

Volkswagen? - ? Crosswind speed? Speed, in miles per hour, 1? MPH = 0.447m/s；

BC? - ? Ballistic ballistic coefficient? Coefficient, representing the fraction of bullet resistance and stability;

MV？ - ? Muzzle? Speed, feet per second, 1? Fps = 0.305m/s

Order:

F0？ =? 166? x？ Bcc? x？ SQRT(MV)[SQRT，Square？ Square root]

Bcc? =? Correct BC according to temperature and pressure.

Altitude 100 meters, temperature 20 degrees Celsius.

Bcc? ≈? 1.08? x？ B.C.

With the above definition, the wind deviation Wi (in inches) can be expressed as:?

Wi？ =? 79.2? x？ r？ x？ Volkswagen? /(MV？ x？ (F0/R？ -? 1.5))

The above formula can be converted into the angle value that needs to be corrected-ew, in MOA (minutes? Yes? Angle, minutes, 1 degree =60 minutes):

Ew？ =? 7563? x？ Volkswagen? /(MV？ x？ (F0/R？ -? 1.5))

The result of the above operation is full value. If it is oblique wind, trigonometric function should be added.

-Gorgeous dividing line.

The above formula has high accuracy, and many foreign ballistic calculation softwares are directly used. However, every time a distance is changed and every wind speed is changed, the calculation must be repeated. There is no time on the battlefield, which is more suitable for rigorous scientific research and design.

The correction is to adjust the position of the crosshair so that the center of the crosshair coincides with the bullet hit point. The adjusting handwheel of the sight has a scale, and the scale unit is-MOA. 1? The MOA is approximately equal to the included angle of 100 yards away 1 inch. 1 = 60moa, a 360 circumference = 1 =60MOA.

The "split angle" on the second floor is MOA.

Finally, I'd like to add ballistic coefficient. Ballistic? Coefficient? - ? BC. ?

Simply put, BC is a characteristic quantity that reflects the bullet resistance and keeps the flying speed. According to it, the instantaneous velocity of bullets at various distances can be calculated. BC is defined according to the law of resistance, which is related to the shape and weight of the bullet, and its accurate value is mainly obtained through experiment+calculation. The ballistic coefficients of various bullets will be published on the websites of American bullet manufacturers.

The definition of ballistic coefficient adopted by the commonly used ballistic calculation software in the United States is: suppose an "ideal" bullet, its ballistic coefficient is 1, and the ratio of other bullets to it is the BC value of this bullet. The higher the BC value, the smaller the flight resistance of the warhead and the more "ideal" the line shape. The most commonly used and basic of these ballistic coefficients is G 1 series.

According to the different resistance laws adopted, the definition of ballistic coefficient is different. Siacci) 1943 resistance law is adopted in China, and the smaller BC value means the smaller resistance, and vice versa. It is necessary to know how to define BC value in reference materials.

The BC value of bullet trajectory parameters commonly used in the United States adopts G 1 series, which is converted by itself:

.223? Remington /5.56x45mm, BC? =? 0.30 1,? MV？ =? 3000? fps。

.308? Winchester /7.62x5 1mm,? BC? =? 0.462,? MV？ =? 2500? fps。

. 30-06/7.62x63mm，？ BC? =? 0.462,? MV？ =? 2700? fps。

.300? Win? Mag/7.62x66mm，？ BC? =? 0.533,? MV？ =? 2900? fps。

-Several commonly used sniper bullets-

M24 adopts M 1 18 special bomb, 7.62x51mm. BC? =? 0.530,? MV？ =? 2580? fps。

7.62x54R rifle bullets used by China and the Soviet Union. BC? =? 0.42,? MV？ =? 2700? Fps, this is the old M 1908 rifle bullet. The 7N 1 and 7N 14 sniper bullets used in SVD are modern special high-precision ammunition, which should be much higher than this value.

A.338 caliber pistol used in AWP/AWM sniper rifles? Lapa? Magnum/8.6x70mm rifle magazine, 19.4g heavy warhead. BC? =? 0.768,? MV？ =? 2850? fps。

Friends who have seen "Life and Death Sniper" must be impressed by the sniper rifle inside. Is that Cheyenne? Tactical company M200 sniper rifle, caliber .408 inch, bullet size 10.36x78mm,? Launch 27.2 grams lost? River warhead? BC? =? 0.934,? MV？ =? 2900? fps。

.50 Browning machine bullet/12.7x99mm, BC? =? 1.076,? MV？ =? 2900? fps。

By comparison, it can be seen that the BC of large caliber bullets is higher, and quantitative data show that this kind of bullets has more advantages in long-range shooting.

-Gorgeous parting line, shall I start spraying? human

What I posted upstairs is not "full ballistics", but a general formula of wind deflection. Think for yourself, is it possible to use the same empirical formula for different guns and different bullets?

I can tell the person in charge. Those you quoted were originally the US Army field teaching model FM? 23- 10, chapter 3-marksmanship shooting, section 3-effect? Yes? Weather weather, from subtitle 3- 12 to 3- 14.

FM？ 23- 10, title sniper? Training sniper tutorial, M24 is used for demonstration? SWS "sniper weapon system", with M3A? 10x42 sight, launching M 1 18 special bomb, I know the contents by heart.

There are many translators in China who use a few colorful pictures and change the name of "sniper textbook" to fool children. All operation and maintenance rules, tactical actions, ballistic data, etc. In fact, it is only for M24, and the US Marine Corps does not use this textbook because they are equipped with M40 rifles. It is even more impossible to imitate SVD/85 in China with his formula, not to mention 5.8 mm.

I wonder which book you picked it from. The translation is quite responsible, the sentences are fluent and the units have been converted. But he made a mistake in the formula you quoted. The original wind speed unit is mph (miles? per？ Hours, miles per hour), he directly replaced it with km/h (kilometers per hour), without conversion, but divided it by 1.609 (because 1 mile = 1609 meters), otherwise the result would be too great.

Send a picture, taken from the original illustration. Is that FM on the left? The cover of 23- 10, take a closer look at whether it is M24 rifle.

The upper right corner is the estimated wind speed from the angle of the flag. The unit is miles per hour. You quote it and multiply it by 1.6, which is kilometers per hour.

At the bottom right is the formula of the original text, which is directly applied by the translator without changing the numbers. And "mile/hour" was directly replaced by "kilometer/hour". Where is 1.6? What is even weirder is that the result is still the same ... what is translated depends on the author's level. ....

At the bottom is the original link, which is dragged to the third section of Chapter 3 (Chapter? 3. festival? III), starting from 3- 12, pretty simple English, something to look at.