Introduction to Long Range Shooting
I have been practicing long range shooting for about ten years. When I bought my first scoped rifle, initially, for deer and wild boar hunting, I began to research and study material about rifle marksmanship, ballistics, and handloading. My intent was to be able to deliver the most accurate and effective shots possible at typical hunting distances (up to ~300yds). I soon discovered that with rifles just like mine, ordinary civilians were shooting at 1000yds, and beyond. I found those subjects fascinating, and the more I learned, the more I wanted to know. With this series of articles, I want to share what I’ve discovered in my research (and range experience).
Let’s start with these questions: what is long range shooting and what does it take to make a shot at long range?
So you want to learn how to shoot long range?
For these articles, we can speak of long range shooting as ranges of 500-600yds, and beyond. Shooting at such distances makes seemingly small factors, such as your heart rate, breathing, physics, and the effects weather, more significant. This adds to the challenge, which, for me, is part of the beauty of this discipline.
What does it take to make a long range shot?
Some of you may recognize this quote from the movie Shooter (2007):
“You know what it takes to make a shot at that range? Everything comes into play that far. Humidity elevation, temp, winds, spin drift. There’s a 6-10 second flight time, so you have to shoot it where the target’s going to be. Even the coriolis effect, the spin of the earth, comes into play.”
They were talking about a shot beyond one mile; however, these elements are still relevant for long distance shooting at closer ranges. There is a bit more involved, including some physics, a little trigonometry, and a few formulas to use for long distance shooting. This math stuff may sound nasty for some of you, but rest assured that’s nothing of too difficult, once you get familiar with it. I’m not a fan of mathematics, so I’ll try to keep it simple. The only other things you need are a willingness to learn, the discipline (and practice) to apply it. Oh, and a rifle, of course!
Speaking of rifles, you may think you need a super-precision-laser rifle, with an astronomical telescope mounted on it chambered in a powerful caliber to shoot long range… You don’t. There are budget solutions, and ways to set up your existing rifle to get started in this beautiful discipline. The same principles can be used effectively with a .22LR rifle with a $200 scope (although, you won’t get the same kind of range as with larger calibers).
What’s most important are solid rifle marksmanship fundamentals. We must endeavor to eliminate, or at least minimize, human error. If your marksmanship skills are flawed, you can go crazy trying to compensate for errors derived not by external variables, but by your hand. In the course of this series, I’ll give you some tips to improve your accuracy. I’ll divide the material into three sections:
Theory
We will examine the physics behind the behaviour of a projectile (bullet) in flight. It is essential to understand this to be able to predict the bullet’s trajectory in order adjust our sights and hit the target at varying distances and conditions.
Weapons System
I will discuss the setup of a typical long range weapons system (i.e., rifle, optics, etc.). I’ll also cover how to maximize the accuracy and consistency of your rifle, how to choose the right optic, and how to select the right ammunition.
Technique
This will be a sort of “how to” section where I’ll take you step by step through long range shooting techniques, starting from zeroing your rifle and building your own ballistic table, and finishing with the observation of the bullet going downrange.
If you have studied and practiced well, you will see your bullet hitting your target, like in this example from Shooter.
Long Range Shooting & External Ballistics
In Long Range Shooting: Ballistics Terms we talk about some general ballistics terminology. Most of what we’ll need to understand about ballistics for long range shooting falls under external ballistics. Here are some of the most common, and important, terms we’ll use.
The first thing you’ll need is to learn ballistics. Here is why:
When you are aiming with your iron sights or with your scope’s reticle, you are actually aiming at a specific point where you know the bullet will be during its flight at your target distance in the specific environmental conditions in which you are shooting. If the distance changes or the environmental conditions change, you have to re-adjust your sights to be able to hit the target again.
Since bullets don’t fly in a straight line, you will have to know its path of trajectory and how it is affected by distance and external forces if you want to be able to consistently hit the target, regardless of distance or environment.
Ballistics Terms
To get started, let’s cover some general terms.
Ballistics: the science that studies the behavior of a projectile, in our specific context, that translates to a bullet firing from a firearm. Ballistics divides in four branches:
Internal ballistics: focuses on what happens within the firearm until the bullet leaves the barrel.
Transitional ballistics: often omitted or associated with either internal or external ballistics, transitional ballistics studies the behavior of the bullet from the moment it leaves the muzzle until the pressure that pushes it forward, generated in the barrel by the powder combustion, settles.
External ballistics: the behavior of the bullet in flight, from the moment when the pressure behind it settles, until the moment it hits the target.
Terminal ballistics: the behavior of the bullet when it hits the target and the effects on it.
Muzzle: the projectile exit end of the barrel.
Muzzle velocity: bullet speed the moment it leaves the muzzle, expressed in fps (feet per second) or m/s (meters per second).
Line of departure: also referred to as bore axis or bore centerline, is the extension of the axis of the barrel. It represents the linear trajectory the bullet would have if undisturbed by external forces.
Line of sights: the straight line between the aligned sights (or scope reticle) and point of aim.
Bullet trajectory: the projectile’s parabolic flight path.
Bullet drop: the distance from the line of departure to the bullet trajectory at a given distance. Drop is measured vertically, as with a plumb-bob, irrespective of the line of departure angle.
You might also like: Long Range Shooting: External Ballistics – Bullet Trajectory
Bullet path: the distance between the line of sight and the bullet trajectory at a given distance. It is always measured perpendicular to the line of sight. Unlike bullet drop, which is always below line of departure, bullet path can be above or below the line of sight. Effectively, the bullet path is where you would see the bullet at a given distance looking through your aligned sights. Bullet path is marked + when above line of sight and – when it is below.
Line of sight height: the vertical distance between the line of sight and the bore axis, measured at the muzzle. For convenience, it is always measured at the scope’s front lens or at the front sight. This introduces a slight error, but it’s negligible considering that the actual angle between the line of sight and the bore axis is generally <1°.
Initial point: where the trajectory and line of sight first intersect. It generally occurs ~25yds from the muzzle. Between initial point and zero range, bullet path is always above line of sight.
Zero range: the farthest distance at which the bullet trajectory and the line of sight intersect. Initial point and zero range are the only two points you can hit exactly where you’re aiming. Zero range is also the distance used as reference for all compensation and adjustments.
Elevation angle/Depression angle: When shooting uphill/downhill, is the angle between the horizontal plane and the line of departure. In other words, the angle of the barrel relative to the horizon.
You might also like: Long Range Shooting: External Ballistics – Elevation
Time of flight: Is the time it takes the bullet to cover the distance between the muzzle and the target.
Residual velocity: Is the speed of the bullet, slowed down by drag, at a given distance.
Drag model: Is the mathematical model used to calculate the effect of air resistance, or drag, on the bullet. Every model is optimized for a specific bullet shape and type. The more common model for rifle bullets are G1 (Ingall’s) and G7.
Ballistic coefficient: a value declared by manufacturers, obtained by mathematical calculations and lab tests, which indicates the aerodynamic efficiency of a bullet. The closer the BC value is to 1, the better the bullet performance. BC increases exponentially as bullet velocity increases. The declared BC is related to a specific drag model, and if manufacturers do not indicate at which model it is referred, it’s generally assumed to be the G1 model (for rifle bullets).
Gyroscopic motion: the rotatory motion, on its horizontal axis, of the bullet in flight. This motion, also called spin, is generated by the barrel’s rifling and is essential for the bullet stabilization and to keep it pointed forward during its flight. It is the same principle that keeps a spinning football stable during a long pass.
Atmospheric pressure: also called barometric pressure, because of the instrument (the barometer) used to gauge it. Is the force that the weight of a column of air exerts at ground level. It is dependent on weather, and varies with elevation (it decreases exponentially with increasing altitude). The SI unit of measurement for atmospheric pressure is Pa (Pascal), but you can find it measured in inHg (inches of mercury, more common in the USA), mmHg (millimetres of mercury) and hPa (hectopascal, or millibar in non-SI denomination). Atmospheric pressure data reported by weather services are generally relative to sea-level (called mean sea level pressure or MSLP), regardless of the elevation of the weather station. Pressure measured with barometers can be relative to sea level, or can be absolute if the instrument measures the real pressure at its altitude.
Speed of sound: Is the velocity of propagation of a sound wave in air. It is dependent on air density and its standard value is 343.2 m/s (1,126 ft/s) at sea level and 20° C (68° F) of temperature. The speed of an object, in our case the bullet, relative to the speed of sound is also indicated with Mach number, where Mach 1 is the speed of sound, Mach 2 is twice the speed of sound and so on. Bullets traveling under the speed of sound are called subsonic. Bullets traveling above the speed of sound are called supersonic. Bullets that travel at more than five times the speed of sound (more than Mach 5) are called hypersonic. The range of speed between Mach 0.8 and 1.2 is called transonic region. The speed of the bullet relative to the speed of sound is important because it dramatically changes aerodynamics.
More information about external ballistics can be found in these books:
“Modern Exterior Ballistics: The Launch and Flight Dynamics of Symmetric projectiles” by Robert L. McCoy. It is has a lot of difficult math in it, so it is appropriate only for those who have a solid knowledge of calculus.
“Applied Ballistics for Long-range Shooting, 2nd Edition” by Brian Litz. More friendly than McCoy’s work and, being more recent, includes more modern technologies and solutions.
“Sierra 5th Edition Rifle and Handgun Reloading Manual” it has a well written section dedicated to exterior ballistics.
