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Range of a projectile

The range of a projectile is the distance traveled by an object launched into the air, subject only to the force of , from its initial projection point to the point where it returns to the same vertical level, assuming a flat launch and landing surface and neglecting air resistance. This concept is fundamental in , describing the motion of objects like cannonballs, baseballs, or arrows in two dimensions, where the forms a parabolic path due to constant velocity and uniformly accelerated vertical motion downward. The range R on level ground is calculated using the formula R = \frac{v_0^2 \sin 2\theta}{g}, where v_0 is the initial speed of the , \theta is of projection relative to the , and g is the (approximately 9.8 m/s² near Earth's surface). This equation derives from combining the displacement x = v_0 \cos \theta \cdot t with the total t = \frac{2 v_0 \sin \theta}{g}, valid under the assumptions of no air , constant , and launch from ground level. For a fixed initial speed, the range is maximized at a launch of $45^\circ, where \sin 2\theta = 1, resulting in R_{\max} = \frac{v_0^2}{g}; since \sin 2\theta = \sin (180^\circ - 2\theta), angles \theta and $90^\circ - \theta yield the same range except at the maximum. Historically, the analysis of projectile range originated with in the early , who first recognized the independence of horizontal and vertical motions, applying it to predict cannon trajectories for military applications. Later refinements by in his Principia (1687) incorporated broader gravitational principles, extending the model to longer-range motions, though the basic parabolic approximation remains a cornerstone of introductory today.

Ideal Projectile Motion

Assumptions and Setup

The range of a projectile refers to the horizontal distance traveled by an object from its point of launch to the point where it strikes the ground, under the influence of alone. This foundational concept in traces its origins to Galileo Galilei's work in the early , where he established that a projectile's path is a parabola, resulting from the superposition of uniform horizontal motion and uniformly accelerated vertical . The ideal model of projectile motion incorporates several simplifying assumptions to enable analytical solutions. These include treating the projectile as a point mass (neglecting its size, shape, rotation, or internal deformations), assuming no air resistance or other external forces beyond gravity, and considering gravitational acceleration as constant at g \approx 9.8 \, \mathrm{m/s^2} directed downward, which yields a parabolic trajectory as if in a vacuum. Additionally, the ground is assumed to be flat and level, with horizontal and vertical motions independent of each other. Analysis begins by establishing a right-handed , with the origin at the launch point, the positive x-axis aligned horizontally in the direction of launch, and the positive y-axis directed vertically upward. The initial velocity \mathbf{v_0}, with magnitude v_0 and directed at an \theta to the horizontal, decomposes into horizontal and vertical components: v_{0x} = v_0 \cos \theta and v_{0y} = v_0 \sin \theta. For flat ground, the —the duration from launch until the returns to the initial height—is determined solely by vertical motion. The vertical position as a of time is given by y(t) = v_{0y} t - \frac{1}{2} g t^2, where the initial vertical position is y(0) = 0. Setting y(t) = 0 to find the impact time yields the t (v_{0y} - \frac{1}{2} g t) = 0, with solutions t = 0 (at launch) and t = \frac{2 v_{0y}}{g} = \frac{2 v_0 \sin \theta}{g} (at impact). This result reflects the of the , as the time to reach maximum height equals the time to descend. Under these ideal conditions, the maximum range is achieved at a launch of $45^\circ.

Range on Flat Ground

In the ideal case of projectile motion on flat ground, the horizontal range R is derived from the kinematic equations assuming constant horizontal velocity and vertical acceleration due to gravity. The horizontal position is given by x = v_0 \cos \theta \cdot t, where v_0 is the initial speed, \theta is the launch angle above the horizontal, and t is time. The time of flight, determined by the vertical motion returning to the initial height y = 0, is t = \frac{2 v_0 \sin \theta}{g}, where g is the acceleration due to gravity. Substituting this into the horizontal equation yields the range formula: R = \frac{v_0^2 \sin 2\theta}{g}. This derivation holds under the assumptions of no air resistance and level terrain, as established in the setup for ideal projectile motion. The range reaches its maximum value when \sin 2\theta = 1, which occurs at \theta = [45](/page/45)^\circ. At this angle, the formula simplifies to R_{\max} = \frac{v_0^2}{g}, representing the farthest distance achievable for a given initial speed on flat ground. A plot of versus launch illustrates the behavior of the formula, showing a symmetric peaking at 45° and approaching zero range at both 0° (pure motion with immediate landing) and 90° (pure vertical motion with no displacement). Complementary angles, such as 30° and 60°, yield identical ranges due to the \sin 2\theta term. For example, with v_0 = 100 m/s and \theta = 30^\circ, the range is calculated as R = \frac{100^2 \sin 60^\circ}{9.8} \approx 886 m, using g = 9.8 m/s² and \sin 60^\circ = \sqrt{3}/2 \approx 0.866. The is highly sensitive to initial conditions: since R \propto v_0^2, doubling the initial speed quadruples the , while the formula shows no dependence on the projectile's , as is independent of in this ideal scenario.

Range on Inclined Ground

In scenarios where the landing surface is an at an \alpha to the , the projectile's range is calculated by resolving the motion into components and to the incline. The g contributes a perpendicular component g \cos \alpha directed toward the plane and a parallel component g \sin \alpha directed down the incline. This simplifies the analysis, as the perpendicular motion determines the , while the parallel motion accounts for the along the slope. For a projectile launched up the incline with initial speed v_0 at an \theta to the , the is t = \frac{2 v_0 \sin(\theta - \alpha)}{g \cos \alpha}, derived from the displacement returning to zero. The R along the incline is then R = v_0 \cos(\theta - \alpha) \, t - \frac{1}{2} g \sin \alpha \, t^2, which simplifies to R = \frac{v_0^2}{g \cos^2 \alpha} \left[ \sin(2\theta - \alpha) - \sin \alpha \right]. This expression accounts for the reduced due to the opposing parallel component. The range up the incline is maximized by choosing \theta_\text{opt} = 45^\circ + \frac{\alpha}{2}, found by setting the derivative \frac{dR}{d\theta} = 0. At this angle, the maximum range becomes R_\text{max} = \frac{v_0^2}{g (1 + \sin \alpha)}. For launches down the incline, the formula adjusts by replacing \alpha with -\alpha, yielding R = \frac{v_0^2}{g \cos^2 \alpha} \left[ \sin(2\theta + \alpha) + \sin \alpha \right], with optimal angle \theta_\text{opt} = 45^\circ - \frac{\alpha}{2} and maximum range R_\text{max} = \frac{v_0^2}{g (1 - \sin \alpha)}. These optimal angles shift from the flat-ground value of $45^\circ to compensate for the incline's geometry. Relative to flat ground, where the maximum range is \frac{v_0^2}{[g](/page/G)}, the uphill case reduces the range due to the additional downward pull along the , while the downhill case increases it by aiding the motion. For small \alpha, the downhill enhancement is modest, but it grows with steeper inclines. As a representative example, consider v_0 = 50 m/s and \alpha = 30^\circ (using g = 9.8 m/s²). For uphill launch, \theta_\text{opt} \approx [60](/page/60)^\circ, yielding R_\text{max} \approx 170 m, compared to the flat-ground maximum of approximately 255 m. For downhill, \theta_\text{opt} = 30^\circ gives R_\text{max} \approx 510 m, more than doubling the flat range.

Real-World Factors

Air Resistance Effects

In real-world conditions, air resistance, or aerodynamic , acts opposite to the of the , significantly altering its from the ideal parabolic path. The drag force is typically modeled as F_d = \frac{1}{2} \rho v^2 C_d A, where \rho is the , v is the instantaneous speed of the , C_d is the dimensionless (dependent on the 's shape and the flow regime), and A is the cross-sectional area perpendicular to the . This quadratic dependence on speed makes drag negligible at low velocities but dominant at higher ones, leading to a deceleration that reduces both the horizontal range and maximum height achieved by the . Qualitatively, shortens the by 10-50% for typical velocities (e.g., 20-100 m/s in or light artillery), with greater reductions at higher launch speeds where the drag force accumulates over longer flight times, and at lower launch angles where the projectile spends more time at higher speeds near the ground. For comparison, the without drag on flat ground is R_\mathrm{ideal} = \frac{v_0^2 \sin 2\theta}{g}, maximized at \theta = 45^\circ. The effect is asymmetric, causing the descending portion of the to be steeper than the ascent, as drag continuously opposes motion regardless of . For low-speed projectiles where the is small (indicating viscous-dominated flow), a linear drag approximation F_d = -b \mathbf{v} (with b a ) simplifies analysis. In this regime, perturbative methods yield a range correction R_\mathrm{actual} \approx R_\mathrm{ideal} \left(1 - \frac{k v_0}{g}\right), where k = b/m relates to the per unit , valid for weak (k v_0 / g \ll 1). This approximation captures the first-order reduction in horizontal , which would otherwise remain in . At higher speeds typical of most projectiles (Reynolds number > 1000), quadratic drag dominates, and the equations of motion become nonlinear differential equations with no closed-form analytical solution for the range or trajectory. Numerical integration, such as Runge-Kutta methods, is required to solve the coupled system m \dot{\mathbf{v}} = m\mathbf{g} - \frac{1}{2} \rho v C_d A \hat{\mathbf{v}}, yielding trajectories that curve more sharply downward and optimal launch angles below 45°. Historical efforts to quantify drag began in the with experiments by Francis Bashforth, who used a to measure the deceleration of cannonballs fired from , establishing early empirical tables for air resistance coefficients up to velocities of several hundred m/s. These measurements, conducted between 1864 and 1880, provided foundational data for ballistic tables, revealing quadratic-like drag behavior for spherical projectiles. As an illustrative example, consider a projectile launched at v_0 = 100 m/s and \theta = 45^\circ on flat ground at (g = 9.8 m/s²), where the ideal is approximately m. With linear (k \approx 0.01 s/m), numerical solutions show the actual reduced to about 930 m, a 9% decrease; stronger (k \approx 0.1 s/m) further shortens it to roughly 500 m, though models for such conditions yield intermediate values around 800 m depending on C_d.

Projectile and Launch Properties

The physical characteristics of a , including its and size, significantly influence its by affecting how it interacts with air resistance. Heavier projectiles tend to retain their initial more effectively against forces because their greater resists deceleration, leading to longer ranges compared to lighter ones of similar shape and size. However, larger projectiles with greater cross-sectional area experience increased due to more surface exposure to the , which can reduce unless compensated by higher . The key quantifying this balance is the ballistic coefficient B = \frac{m}{C_d A}, where m is the , C_d is the , and A is the cross-sectional area; higher values of B indicate better retention and extended . The shape of the projectile plays a critical role in minimizing drag, with streamlined designs outperforming blunt ones. Blunt-nosed or spherical projectiles have higher drag coefficients, typically around 0.47 for smooth spheres at speeds, resulting in substantial energy loss and shortened range. In contrast, pointed or ogive-nosed shells, common in , achieve lower drag coefficients of approximately 0.1 to 0.15 in streamlined configurations, allowing for greater range by reducing form drag. Spin stabilization, imparted by rifling, enhances projectile stability through gyroscopic effects, reducing drag from tumbling and helping maintain range. The Magnus force generates a lateral drift but has minimal direct impact on range. Launch velocity influences range through distinct aerodynamic regimes: subsonic speeds (below Mach 1) exhibit relatively steady drag, while supersonic velocities (above Mach 1) encounter a drag spike near Mach 1.2 during the transonic transition, where compressibility effects sharply increase resistance and reduce range. For example, a 1 kg spherical projectile launched at 200 m/s experiences approximately 40% range reduction compared to ideal conditions due to high drag, whereas a 1 kg aerodynamic shell of similar mass sees only about 20% reduction, highlighting the impact of shape on practical performance.

Barrel and Environmental Influences

The design of the barrel in firearms and launchers significantly influences the initial velocity and stability of a projectile, thereby affecting its range. Longer barrels allow more complete combustion of the propellant, resulting in higher muzzle velocities; for instance, in AR-15 rifles chambered in 5.56mm, a 20-inch barrel achieves an average muzzle velocity of 3098 feet per second (fps), compared to 2697 fps from a 10.3-inch barrel, representing approximately a 15% increase for nearly double the length. Extending a barrel from 16 inches to 24 inches in a .308 Winchester rifle can boost effective range from around 500 meters to 650 meters by enhancing velocity and reducing drop, though diminishing returns occur beyond optimal lengths due to friction losses. Rifling within the barrel imparts to the for gyroscopic , with rates measured as the distance for one full (e.g., 1:10 indicates one turn per 10 inches). A 1:10 rate effectively stabilizes .30-caliber bullets weighing up to 220 grains, maintaining accuracy and preventing tumbling out to ranges of 1 kilometer or more. Typical muzzle velocities vary by weapon type: handguns like 9mm pistols average 300–400 meters per second (m/s), rifles such as the reach 900 m/s, and pieces like 155mm howitzers achieve around 800 m/s, directly scaling with barrel design and charge. Environmental conditions during flight further modify range by altering air resistance and trajectory. At higher altitudes, reduced air density lowers drag; for example, at 3000 meters elevation, where density is about 70% of , projectile range can increase by 10–20% compared to sea-level conditions due to less deceleration. Temperature and humidity also influence drag through air density changes: warmer temperatures or higher slightly decrease density, reducing drag by up to 5% and extending range, while colder or drier conditions increase it proportionally. Wind introduces lateral and vertical deflections that can substantially reduce . A 10 m/s (approximately 22 mph) headwind slows the , potentially decreasing range by up to 15% over medium distances by increasing and drop, while a of the same speed causes deflection proportional to —e.g., up to 1–2 meters at 500 meters for a typical —necessitating aim adjustments. These factors interact with barrel-induced spin for overall stability, as the imparted rotation helps counter minor yaw from .

Long-Range Ballistics

In long-range ballistics, for distances exceeding 10 kilometers, the of the Earth significantly influences projectile trajectories, as the path arcs over the horizon rather than following a flat plane. This effect effectively increases the range and maximum altitude of the shot by altering the of the fall under , necessitating corrections that account for the momentary variation in the direction of gravitational attraction along the curved path. For instance, in early 20th-century naval gunnery calculations, the curvature correction was essential for trajectories beyond 20 kilometers, where the line-of-sight distance underestimates the true horizontal separation due to the Earth's spherical shape. The introduces the Coriolis effect, a in the rotating frame that deflects projectiles laterally from their inertial path. In the , this deflection is to the right for eastward or northward firings, with the magnitude proportional to the , velocity components, and ; southward firings deflect leftward. For a 50-kilometer shot at mid-latitudes, the Coriolis effect can cause an eastward deflection of approximately 100 meters, requiring predictive adjustments in fire control systems to maintain accuracy. Atmospheric over extended paths leads to exponential velocity decay, far beyond simple quadratic approximations, demanding for precise modeling rather than closed-form solutions. The Siacci method, developed in the late , addresses this by segmenting the into zones of approximately constant , using tabulated functions to approximate the differential and enable rapid computations via precomputed ballistic tables. This approach remains foundational for long-range predictions, though modern variants incorporate variable for greater fidelity. In , the absence of would extend ranges to roughly twice those observed in atmosphere for typical high-velocity projectiles. Artillery systems exemplify these challenges: the World War II-era German 88 mm Flak gun achieved a maximum range of about 15 kilometers under optimal conditions, limited primarily by drag and gravity. Contemporary multiple launch rocket systems, such as the M270, achieve ranges up to approximately 70 km with guided rockets like the GMLRS, or up to 150 km using extended-range guided variants like the GMLRS-ER (achieved in 2023 tests, with production scaling as of 2025). Conventional examples highlight the precision demands, such as naval guns like the U.S. 16-inch/50 caliber, which reached maximum ranges of approximately 40 kilometers; here, ballistic computations integrated and rotation effects, as a 0.5° error could propagate to a range miss exceeding 1 kilometer due to the sensitivity of long arcs to angular perturbations. While intercontinental ballistic missiles encounter amplified versions of these effects during their global arcs and reentry, long-range primarily concerns such suborbital, conventional systems where integrated corrections ensure viable accuracy.

References

  1. [1]
    4.3 Projectile Motion – University Physics Volume 1 - UCF Pressbooks
    The maximum horizontal distance traveled by a projectile is called the range. Again, the equation for range is valid only when the projectile lands at the same ...4.3 Projectile Motion · Time Of Flight, Trajectory... · Problems
  2. [2]
    Projectile Motion – Introductory Physics for the Health and Life ...
    He used it to predict the range of a projectile. On level ground, we define range to be the horizontal distance R traveled by a projectile. Galileo and many ...
  3. [3]
    Projectile motion
    Reasoning: We have motion with constant acceleration in two dimensions, or projectile motion. The range of a projectile over level ground is R = (v02sin2θ0)/g.
  4. [4]
    5.3 Projectile Motion - Physics | OpenStax
    Mar 26, 2020 · Projectile motion is the motion of an object thrown (projected) into the air when, after the initial force that launches the object, ...
  5. [5]
    Galileo's Discovery of the Parabolic Trajectory - Scientific American
    He showed that a body falling with a horizontal component of motion describes a parabola. It has been thought that he did so solely by principle, ...
  6. [6]
    [PDF] Projectile Motion Sample Problem And Solution Projectile Motion ...
    Q1: What are the assumptions made in the idealized projectile motion ... acceleration, and that the projectile is a point mass (neglecting its size and shape).
  7. [7]
    standard acceleration of gravity - CODATA Value
    standard acceleration of gravity $g_{\rm n}$ ; Numerical value, 9.806 65 m s ; Standard uncertainty, (exact).
  8. [8]
    3.4 Projectile Motion – College Physics - UCF Pressbooks
    Identify and explain the properties of a projectile, such as acceleration due to gravity, range, maximum height, and trajectory.
  9. [9]
    Hitting a Home Run
    Both maximum ranges occur at a 45 degree angle. Note that the range is equal at angles 30 and 60, 35 and 55, and 40 and 50 for the graph with no drag. This is ...
  10. [10]
    [PDF] UNIT 6: GRAVITY AND PROJECTILE MOTION - Galileo
    How does the mass of the falling object affect its acceleration? Is the gravitational force constant independent of the mass of the falling object, just the way ...
  11. [11]
  12. [12]
    Projectile Motion with Air Resistance - Richard Fitzpatrick
    It is clear, from the above equation, that air drag causes the projectile's horizontal velocity, which would otherwise be constant, to decay exponentially ...
  13. [13]
    [PDF] Topic 1 | Projectile Motion with Air Resistance
    Air resistance, or drag, significantly affects projectile motion. It's calculated using air density, area, and a drag coefficient, and is opposite to the  ...
  14. [14]
    [PDF] 2 The aerodynamics of the beautiful game 1 Introduction - MIT
    Incorporating air drag reduces B from ∞ to 0.1 for the case of a football in flight, and so reduces the predicted range of goal kicks from 120 m to 60 m, which ...
  15. [15]
    [PDF] Section 2.3 Trajectory and range of a projectile in a linear medium 1
    The "trajectory" is the curve in space along which the particle moves. ▷Horizontal position, x(t). Note: x(t) approaches a maximum distance, x.Missing: formula | Show results with:formula
  16. [16]
    Subtle features in projectile motion with quadratic drag found ...
    Feb 1, 2022 · Many attempts have been made at finding the trajectory for the projectile problem with quadratic drag. However, no complete analytical solution is possible.
  17. [17]
    Revised account of the experiments made with the Bashforth ...
    Sep 24, 2007 · Revised account of the experiments made with the Bashforth Chronograph, to find the resistance of the air to the motion of projectiles.Missing: cannonball drag
  18. [18]
    Highways and Byways in the History of High Rate Mechanical Testing
    Feb 24, 2020 · Bashforth F (1870) Reports on experiments made with the Bashforth chronograph to determine the resistance of the air to the motion of ...
  19. [19]
    [PDF] Computational Assignment 2 2-D Projectile Motion with Drag - SIUE
    Nov 15, 2006 · We studied the range of the projectile with both no drag and with linear drag. In doing this experiment, I found for an initial velocity of 100m ...
  20. [20]
  21. [21]
  22. [22]
    External Ballistics ‑ Hornady Manufacturing, Inc
    Ballistic coefficients are calculated not only with reference to a standard projectile but with reference to standard test conditions as well. All ballistic ...
  23. [23]
    Drag of a Sphere | Glenn Research Center - NASA
    Jun 30, 2025 · Where D is equal to the drag, ρ is the air density, V is the velocity, A is a reference area, and Cd is the drag coefficient. Drag Coefficient.
  24. [24]
    [PDF] Drag Coefficient Measurements for Typical Bomb and Projectile ...
    Aug 28, 1990 · This method provided the experimental drag coefficient value for the actual flight attitude, but for a very low Mach number (on the order of ...
  25. [25]
    [PDF] Magnus Effects on Ballistic Trajectories. - DTIC
    The Increased spin rate extends the projectile impact point both downrange and cross range due to a slight increase in tine of flight ... - ) The effect of Magnus ...<|separator|>
  26. [26]
    Mach Number
    Because of the high drag associated with compressibility effects, aircraft do not cruise near Mach 1. Supersonic conditions occur for Mach numbers greater than ...
  27. [27]
    [PDF] Aerodynamic Drag Modeling for Ballistics
    To calculate a drag force for Mach. 1, 2, and 3, we simply multiply the dynamic pressure at each of these speeds by the projectiles frontal area giving: 6.9 ...
  28. [28]
    AR-15 Barrel Length and Velocity Test - Sonoran Desert Institute
    Aug 9, 2023 · Longer AR-15 barrels impart more force, increasing velocity. A 20-inch barrel averaged 3098 fps, while a 10.3-inch averaged 2697 fps.
  29. [29]
    The AR-15 Barrel Cheat Sheet: Everything You Need to Know
    Feb 28, 2022 · It increases the effective range of the bullet. Longer barrels generally correspond to lower pressures inside of the rifle. That, in turn ...
  30. [30]
    Rifle Barrel Twist vs. Bullet Weights - RifleShooter
    Mar 26, 2021 · In .30 caliber, a 1:10 twist will stabilize a wide range of bullet weights. 7mm bullets tend to be longer for caliber than .30 caliber bullets ...
  31. [31]
    How Fast Do Bullets Travel? - Wideners Shooting, Hunting & Gun Blog
    Mar 30, 2022 · Generally, velocities range from 400 to 4,600 feet per second. How fast do bullets travel? Hopefully, you have your answer and a better general ...
  32. [32]
    Ballistics: Altitude and Air Pressure within AccurateShooter.com
    Higher altitude reduces air density, decreasing bullet drop. Local barometric pressure, not just altitude, is key, and air temperature also affects bullet ...
  33. [33]
    Ballistic Effects of Altitude, Temperature, and Humidity - Lilja Barrels
    Jan 23, 2015 · Because humidity has such a small effect it can be ignored. Increasing the temperature or altitude will increase the ballistic coefficient.
  34. [34]
    How To Beat The Wind - RifleShooter
    Feb 13, 2019 · Wind deflection is a direct linear function of wind velocity. At any given distance a 20-mph wind pushes a bullet twice as far as a 10-mph wind.
  35. [35]
    New Ballistic Corrections | Proceedings - August 1921 Vol. 47/8/222
    (2) The curvature of the earth; increasing the range and the altitude; and momentarily varying the direction of the gravitational attraction. (3) The westerly ...
  36. [36]
    Earth's Curvature and Battleship Gunnery | Math Encounters Blog
    Dec 20, 2017 · In this post, I want to examine how the curvature of the Earth affected the gunnery direction. Curvature corrections are only needed for very long-range ...
  37. [37]
    Ballistics App Tips: The Coriolis effect - Lapua
    Jul 24, 2020 · The Coriolis Effect describes the pattern of deflection taken by objects not firmly connected to the ground as they travel long distances around the Earth.
  38. [38]
    Does The Spinning Earth Affect Long Range Shooting?
    A slower bullet traveling the same distance will experience greater Coriolis deflection because it remains in flight longer, allowing more time for the Earth ...
  39. [39]
    [PDF] How External Ballistics Programs Work
    Bottom line for Siacci: If you use a standard drag function that closely matches ... The complexity of Mach dependant projectile drag belongs in the solution ...
  40. [40]
    The Mathematics of Exterior Ballistic Computations - jstor
    the Siacci method continued in use as an auxiliary until about 1935. It then was dropped completely. 3. Modifications of the Siacci method. Shortly after ...
  41. [41]
    Germany's Versatille 88mm Gun - Warfare History Network
    Mar 8, 2016 · The maximum range was 14,860 meters and the maximum vertical range was given at 10,600 meters. As the gun's use expanded to other roles so did ...
  42. [42]
    Long-range rocket artillery munitions: A market overview - Euro-sd
    Mar 13, 2025 · Since 2018, Lockheed Martin has been developing the Extended Range (ER) GMLRS capable of striking targets located over 150 km from the launcher.
  43. [43]
    CHAPTER-17-B-EXTERIOR-BALLISTICS - Gene Slover's Navy Pages
    2,500-foot-second gun, firing at a range of 10,000 yards. ... 296 yards short. Note that the correction to compensate for this error in range is ADD 296 YARDS.