Ar 15 Bullet Trajectory Calculator

Accurate bullet trajectory calculation is essential for precision shooting with AR-15 rifles. This calculator helps you determine bullet drop, wind drift, and effective range based on your specific ammunition and environmental conditions.

What is AR-15 Trajectory?

AR-15 trajectory refers to the path a bullet follows when fired from an AR-15 rifle. The trajectory is influenced by several factors including:

Bullet weight and type
Muzzle velocity
Distance to target
Barometric pressure
Temperature
Wind speed and direction

Understanding trajectory is crucial for accurate shooting, especially at longer ranges where bullet drop becomes significant. The calculator helps you account for these variables to ensure your shots hit their intended targets.

How to Use This Calculator

Enter your bullet weight in grains
Select your bullet type (FMJ, JHP, etc.)
Input the muzzle velocity in feet per second (FPS)
Enter the distance to your target in yards
Provide current barometric pressure in inches of mercury (inHg)
Enter the current temperature in degrees Fahrenheit (°F)
Specify wind speed in miles per hour (MPH) and direction
Click "Calculate" to see the results

The calculator will display bullet drop, wind drift, and an estimated effective range. You can also view a trajectory chart showing the bullet's path.

Bullet Drop Formula

The bullet drop is calculated using the following formula:

Bullet Drop (inches) = (Bullet Weight × Distance²) / (Muzzle Velocity² × 700)

This formula accounts for the natural drop of a bullet due to gravity as it travels through the air. The calculator applies additional corrections based on atmospheric conditions.

Wind Drift Formula

Wind drift is calculated using:

Wind Drift (inches) = (Wind Speed × Distance) / (Muzzle Velocity × 100)

The direction of wind drift depends on whether the wind is coming from the shooter's left or right. The calculator adjusts for this based on your input.

Example Calculation

Let's calculate the trajectory for a 60-grain FMJ bullet fired at 2,800 FPS to a target 500 yards away with standard atmospheric conditions (29.92 inHg, 70°F, no wind):

Parameter	Value
Bullet Weight	60 grains
Bullet Type	FMJ
Muzzle Velocity	2,800 FPS
Distance	500 yards
Barometric Pressure	29.92 inHg
Temperature	70°F
Wind Speed	0 MPH

The calculator would show approximately 12.5 inches of bullet drop at this range. With wind, the drift would be calculated based on the wind speed and direction you specify.

Frequently Asked Questions

What is the most accurate way to measure bullet drop?: The most accurate method is to use a ballistic calculator that accounts for all relevant variables including bullet weight, muzzle velocity, distance, and atmospheric conditions.
How does temperature affect bullet trajectory?: Warmer temperatures cause the air to expand, which can slightly increase bullet drop. Colder temperatures have the opposite effect. The calculator adjusts for temperature variations.
What is the effective range of an AR-15?: The effective range of an AR-15 depends on the specific rifle and ammunition, but generally ranges from 300 to 500 yards. The calculator helps determine the practical range based on your specific setup.
How does wind affect bullet trajectory?: Wind can cause significant drift, especially at longer ranges. The calculator accounts for wind speed and direction to help you compensate for these effects.
What is the difference between FMJ and JHP ammunition?: FMJ (Full Metal Jacket) ammunition is designed for accuracy and long-range shooting, while JHP (Jacketed Hollow Point) ammunition is optimized for stopping power at shorter ranges. The calculator can help you choose the right type for your needs.