Formulas

Distance

Milliradian-based Reticles
YARDS

Target Size (Inches) x 27.77 ÷ Target Size (Mils) = Distance (Yards)

10 (Inches) x 27.77 ÷ .2 (Mils) = 1,388 Yards

10 x 27.77 ÷ .2 = 1,388 Yards

Target Size (Yards) x 1000 ÷ Target Size (Mils) = Distance to Target (Yards)

2 (Yards) x 1000 ÷ .25 (Mils) = 800 Yards

2 x 1000 ÷ .25 = 800 Yards

METERS

Target Size (cm) x 10 ÷ Target Size (Mils) = Distance (Meters)

25.4 (cm) x 10 ÷ .5 (Mils) = 508 Meters

25.4 x 10 ÷ .5 = 508 Meters

Target Size (Inches) x 25.4 ÷ Target Size (Mils) = Distance to Target (Meters)

10 (Inches) x 25.4 ÷ .25 (Mils) = 1,016 Meters

10 x 25.4 ÷ .25 = 1,016 Meters

Target Size (Meters) x 1000 ÷ Target Size (Mils) = Distance to Target (Meters)

2 (Meters) x 1000 ÷ 2.8 (Mils) = 714 Meters

2 x 1000 ÷ 2.8 = 714 Meters

Minute of Angle-based Reticles

YARDS

Target Size (Inches) x 95.5 ÷ Target Size (MOA) = Distance to Target (Yards)

10 (Inches) x 95.5 ÷ 1.25 (MOA) = 764 Yards

10 x 95.5 ÷ 1.25 = 764 Yards

METERS

Target Size (Inches) x 87.3 ÷ Target Size (MOA) = Distance to Target (Meters)

72 (Inches) x 87.3 ÷ 5.5 (MOA) = 1,142 Meters

72 x 87.3 ÷ 5.5 = 1,142 Meters

Target Size (Meters) x 3438 ÷ Target Size (MOA) = Distance to Target (Meters)

Target Size (cm) x 34.38 ÷ Target Size (MOA) = Distance to Target (Meters)

Meters to Yards - Yards to Meters

Conversion

Meters to Yards
Multiply by 1.0936
Ex. 500 Meters x 1.0936 = 547 Yards

Yards to Meters
Divide by 1.0936
Ex. 900 Yards ÷ 1.0936 = 823 Meters

MOA to MILS - MILS to MOA

MOA to MILS

Divide by 3.5

Ex. 5 MOA ÷ 3.5 = 1.42 MILS

MILS to MOA

Multiply by 3.5

Ex. 2.6 MILS x 3.5 = 9.1 MOA

QUICK WIND/B.C. METHOD
(This is the best and fastest way to read the wind)

Wind Speed / Gun Number x 1/1000 Distance x Cosine Angle
12 / 4 x .4 x .5 = .6 Mils

Wind - 12 mph from 1 o’clock
Distance - 400 yards

Count by 4 up to 12 or divide 12 by 4 = 3
3 x 4 (4 because we are at 400 yards) = 1.2 Mils
1.2 Mils is my full-value wind hold.
Now I need to adjust for the wind angle.
The cosine for 1 o'clock is .50. You can think of this in a few different ways and pick what is easiest for you.

1.2 x .50 = .6 Mils
12/2 = .6 Mils
50% of 12 = .6 Mils

FOR MORE INFORMATION ON QUICK WIND SEE QUICK WIND IN MY BLOG

Tactical Loophole Shooting

BH x C / distance to loophole = mils - DOPE

BH - Bore Hight in Inches
C - BH in Mils C = BH x 25.4
Distance to loophole in feet

1.75 x 45 / 12 = 6.56 mils - dope

Next, subtract your Dope from 6.56

at 500 yards, my Dope is 2.8 mils

6.56 - 2.8 = 3.76 mils
Our bullet will clear the loophole if we have 3.76 mils of clearance.

This formula will work with 99% of rifles
BH x 80 / distance to loophole - Dope

WINDROSE

Cosine Angle Calculator

1/4 Windrose

Multiply the wind speed or Mil hold by the cosine for th e wind angle.

Full Windrose

EX: 12 MPH x .707 (45°) = 8.454 MPH

EX: 1.2 (Mil hold) x .707 (45°) = .85 Mils

Spin Drift

Drift - Spin drift in inches, in the direction of rifling twist

SG - The gyroscopic stability factor

TOF - The bullets time of fight

Drift = 1.25 x (SG + 1.2) x TOF ^ 1.83.

Ex.

SG - 1.83
TOF - .7 @ 500 Yards

1.25 (1.83 + 1.2).7^1.83 = 1.97 Inches

TOF @ 1000 = 1.75

1.25 x (1.83 + 1.2) x 1.75^1.83 = 10.54 Inches

Coriolis Effect

F = 2 * m * v * ω * sin(α)

F - is the Coriolis force.

m - is the mass of the moving object.

v - is the velocity of the moving object.

ω - is the angular velocity of the Earth.

α - is the latitude at which the object is located.

ω = 2π/24h ≈ 0.0000727 1/s (2π means 360°

Eötvös Effect

1+2*Ω*MV/-32.2*cos(Rads(Lat))*sin(Rads(Azimuth))

Magnus Effect

Fm = S (w × v)

Fm = Magnus force vector

w = Angular velocity vector of the object

v = Velocity of the object
S = Air resistance coefficient across the surface of the object

Angle of Fire

Distance * (Cos = Corrected Distance

Ex. 500 yds at a 25° angle
500 * .940 = 470 yds