Long range shooting

The distances normally considered to be "long range" is weather- and caliber-dependent, and long range may be defined as stretching the distance which the firearm and ammunition is capable of making consistent hits. Generally some may claim that for the .22 LR cartridge any distances over 100 meters (109 yards) is considered long range. For centerfire intermediate rifle calibers, some might say that everything over 300 to 400 m is considered long range, while some may claim that long range "starts" at 500 m. At the longer ranges the bullets will have a longer flight time, and on days with good lighting and weather conditions one can even see a brief trail of wake behind a supersonic bullet, known as a bullet trace, due to turbulences creating visible refractive disturbances in the air. A bullet trace should not be confused with a vapor trail, which is sometimes observed when firing under rare conditions due to changes in air pressure around the bullet. While the bullet trace is usually only observable directly from behind the shooter, a vapor trail from a bullet is observable from any direction.[1][2][3] Some believe you really get "the feel" of long range shooting when you have time to see the bullet fly towards the target, and then dive below or swing past, just when you were sure you would hit it. Weather conditions may also affect what is considered long range for a given firearm configuration. For instance a professional shooter may be able to repeatably hit a given size target, i.e. a 100 mm ring, at 1000 meters (0.1 mil target difficulty) in low and predictable wind, while the same 100 mm target may be near impossible to hit in heavy and varying wind at 200 meters (0.5 mil target difficulty).

A spotting scope is often used to observe hits and provide sight corrections, and can aid in seeing bullet trace. Bullet trace can often easily be seen in humid weather, but also on cool and sunny days. There are several possible explanations of the phenomenon. The main cause is probably contrails which appear around the bullet due to pressure changes as the bullet travels through the air, thereby causing a short change in the light refraction of the air. In order for the shooter to see their own bullet trace, the bullet trajectory must be within the field of view of their scope sight. In practice this often means the shooter has to dial down the magnification somewhat (i.e. to 10× magnification).

To succeed at long range shooting, one must have good shooting skill fundamentals, a rifle with good precision and as consistent ammunition as possible (mainly to achieve a consistent muzzle velocity). In addition, a variety of external factors must be taken into account with regard to ballistics calculation, including:

• Wind (both by the shooter and along the whole flight path to the target).[4][5]
• Bullet shape and weight, trying to achieve the highest possible ballistic coefficient ("BC")[6]
• Air pressure, altitude and (to a certain degree) humidity[7]
• Temperature (including air, ammunition and barrel temperature) [8]
• Spindrift,[9] an effect caused by the rotation of the bullet
• Coriolis effect,[10] caused by the Earth's rotation
• Mirage,[11] which causes the shooter to hit high and to the side if there is a little wind
• Angle to the target (called "cosine angle"),[12] either up or downhill

etc.

All these parameters can also be used at shorter distances, but the effect they pose is so small that they generally can be disregarded. At short distances the accuracy of the shooter, rifle and ammunition will often mask the very small effect these factors will have.

Wind estimation

Observing mirage, seen as "waves" above this hot road, is often used to estimate wind speed in long range shooting.

For long range shooting it is important to compensate for the wind by observing the wind's strength and direction, and then adjust the sights accordingly by rules of thumb. Wind force can be estimated by feeling the wind at the shooting position and seeing signs of it in the terrain. After for instance guessing the wind strength in meters per second (m/s), this wind value can be transferred to a sight correction in number of clicks. This rule of thumb applies to winds that come 90 degree from the side (full value), however winds coming from an angle must be taken into account by applying less sight adjustment.

Long range wind estimation table based on the Beaufort scale

Wind speed (m/s and mph)	Land conditions
Calm <0.3 m/s <1 mph	Smoke rises vertically.
Light Air 0.3-1.5 m/s 1–3 mph	Direction shown by smoke drift but not by wind vanes.
Light Breeze 1.6–3.3 m/s 4–7 mph	Wind felt on face; leaves rustle; wind vane moved by wind.
Gentle breeze 3.4–5.5 m/s 8–12 mph	Leaves and small twigs in constant motion; light flags extended.
Moderate breeze 5.5–7.9 m/s 13–18 mph	Raises dust and loose paper; small branches moved.
Fresh breeze 8-10.7 m/s 19–24 mph	Small trees in leaf begin to sway; crested wavelets form on inland waters.
Strong breeze 10.8–13.8 m/s 25–31 mph	Large branches in motion; whistling heard in telegraph wires; umbrellas used with difficulty.

There are many different long range disciplines, competing both at known (KD) and unknown distances (UKD), individually or in teams (shooter and spotter). In UKD competitions the marksman must also judge the distances, for example by comparing a known size target with angular mil hashmarks inside their scope (called "milling") to calculate the distance. Sometimes a laser rangefinder may also be used, if permitted.

View through a 20x power scope sight with mil-dots at 300 yards (274 meters).

The ideal scope sight magnification for different types of long range shooting depends on application, scope quality and user preference. Different applications may have different shooting distances, light conditions, target sizes and target contrast against the background. Ideally scope magnification should be high enough while still being comfortable and safe to use.

Pros of high scope magnification are:

• Easier to see the target at distance.[16]
• Easier to spot whether the round was a hit or miss, and easier to estimate sight corrections.

Cons of high scope magnification are:

• The sight picture appears to shake easier by movement of the shooter.[17]
• Mirage becomes more visible.[18]
• Less field of view makes it more difficult to initially find the target, and to see the surroundings of the target.[19]
• Less light transmission gives a darker image in the scope when compared to a scope with larger tube and objective diameter or inside the same scope at a lower magnification.
• Smaller exit pupil diameter makes it more difficult to get in the correct position behind the scope.

Mirage is a light distortion caused by temperature differences between the air and ground making it difficult to get a clear sight picture of the target. Mirage becomes more apparent the higher the magnification, but at what magnification mirage starts to become an issue depends on weather conditions.[20]

• Benchrest shooting
• External ballistics

• Video: 2012 European F-Class Rifle Championships at Bisley Shooting Ground in the UK.
• Video: Teamwork: Spotter & Shooter - Long Range Rifle Tip (by National Shooting Sports Foundation)
• Video: T-Class - The ultimate tactical sniper competition