model internals [how it works]
Contents
1. gt The horizontal distance to move the impact point Enter a positive value to move the impact point right a negative value to move the impact point left Tip Use 3 5 rounds and average the distance from the target center for best results SHOOTER S REFERENCE V3 sight in zero sight in target distance and correction adjustment vertical target distance adjustment in yds up down solution scope moa mils vertical adjustment U3 4 U10 horizontal adjustment in right left horizontal moa mils L3 4 L1 0 To calculate scope adjustment enter J distance to target and distance of group center from target center Use 3 5 rounds and average distance for best results e PA CROWN MOLDING it s Any angle Any place Calculate FREE CALCULATOR once and measure twice nge estimate target range using mil scope Estimating Range Using a Mil MOA Scope The range page provides a simple method of estimating the range of a target given its actual size and apparent size in mils or MOA t actual size gt Required in inches or centimeters gt The actual height of the target area being measured scope size gt Required in mils or MOA gt The apparent height of the target area being measured scope units Required choose mils or MOA gt Determines table increment display table increment gt Required choose 1 8 or 1 10 increments g2. Bore angles are typically very small around 0 05 to 0 10 degrees However a small variation can result in several inches of error at 500 yards Shooter s Reference calculated zero at the actual zero distance Is 0 05 inches 1 2 mm Horizontal Distance y Parabolic Path d Line of Sight Angles Exaggerated tor Illustration Source http en wikipedia org wiki Rifleman s rule The zero distance and scope height entered on the Setup page is used to generate a custom drop table for your cartridge and firearm The ballistics model uses an iterative process that takes into account the cartridge bullet and ambient conditions to determine the bore angle model internals how it works The zero correction in mils and moa Is displayed on the solve page and the bore angle is used by the ballistics model along with the inclination angle to generate the solution at the target distance as well as the custom drop table Projectile Motion Simulation Once the ambient conditions firearm and cartridge bullet parameters are set the ballistics model generates a solution at the user specified distance on the solve page and for each distance point in the accompanying drop drift table page Bullet drag is calculated using one of two formulas depending on whether the user has selected the use BC option on the setup page It is recommended that the use BC option is not used and that instead a bul
3. or meters Measurement Units Metric units are used internally Input and display units can be toggled at any time by checking unchecking this box input units Required in yards or meters SHOOTER S REFERENCE V3 setup cartridge and bullet parameters bullet caliber bullet bullet in or mm weight gr bullet bc model 5 G2 muzzle muzzle energy b velocity fps ft lbs adiu G gt ambient conditions wind speed wind direction elevation deg ft so temperature humidy pressure deg F rh in Hg firearm setup scope height zero dist units in yds check for solve enter target data and solve model Find a Solution The target distance bearing and inclination angle are entered on the Solve page Press the solve button to calculate the solution distance gt The line of sight distance to the target gt Required in yards or meters t bearing gt The target bearing gt Required in degrees t inclination angle gt The target inclination angle see illustration on page 13 Hequired in degrees The line of sight distance also referred to as the slant range is the straight line distance as measured to the target The ballistics model uses the Rifleman s Rule to calculate the horizontal distance to the target This compensates for uphill or downhill shooting situations SHOOTER S REFERENCE V3 solve target parameters distance bearing incl
4. yds E ft lbs D in W in Manufacturer SR Model G7 SR Model G1 BC Manufacturer SR Model G7 SR Model G1 BC Manufacturer SR Model G7 SR Model G1 BC Manufacturer SR Model G7 SR Model G1 BC 2900 2900 2900 3548 3548 3548 5 5 0 0 0 0 0 0 100 2726 2730 2710 3134 3145 3097 1 6 1 6 1 6 0 6 0 7 0 7 200 2558 2566 2526 2 60 2777 2691 0 0 0 0 0 0 2 4 2 4 2 7 300 2396 2406 2348 2422 2441 2325 6 9 1 73 55 5 4 6 2 400 2240 2249 2178 27 2133 2001 959 20 8 21 8 10 1 99 S 500 2090 2093 2018 1843 1847 1718 39 8 42 7 44 9 16 4 16 0 18 2 229 S 0 4 1 8 300 Win Mag Drop inches 300 Win Mag Drop inches G1 Model with BC Correction Manufacturer s Data G7 Model Manufacturer s Data 100 200 300 0 100 200 300 400 model performance data 338 winchester lapua magnum V fps 338 Lapua Mag Winchester GM338LM Manufacturer s Data vs Shooter s Ref Model Distance yds E ft lbs D in W in Manufacturer SR Model G7 SR Model G1 BC Manufacturer SR Model G7 SR Model G1 BC Manufacturer SR Model G7 SR Model G1 BC Manufacturer SR Model G7 SR Model G1 BC 2950 2950 2950 4830 4830 4830 5 5 5 0 0 0 0 0 0 100 2789 2785 2775 4318 4305 4275 15 15 1 5 0 5 0 6 0 6 200 2634 2625 2606 3851 3824 3768 0 0 0 0 0 0 21 22 2 4
5. 300 2484 2469 2441 3426 3382 3307 6 5 6 7 6 8 4 9 5 1 5 4 400 2339 2316 2282 3037 2977 2890 18 5 19 8 20 2 8 8 9 2 99 500 2199 2166 2130 2685 2603 2519 571 40 4 41 4 14 3 14 9 159 338 Lapua Mag Drop inches 338 Lapua Mag Drop inches G1 Model with BC Correction Manufacturer s Data G7 Model Manufacturer s Data 0 100 200 300 400 100 200 300 400 model performance data 308 winchester 308 Win Winchester AE308D Manufacturer s Data vs Shooter s Ref Model Distance yds 0 100 200 300 400 500 A 500 V fps Manufacturer 2820 2597 2385 2183 1990 1808 SR Model G7 2820 2598 2384 2175 1967 1767 41 SR Model G1 2820 2575 2342 2122 1921 1749 59 E ft lbs Manufacturer 2648 2246 1894 1586 1319 1089 SR Model G7 2648 2248 1892 1576 1289 1040 49 SR ModelG1 BC 2648 2209 1826 1499 1229 1018 71 D in Manufacturer 1 5 1 8 0 0 8 0 23 3 47 2 SR Model G7 1 5 1 8 0 0 8 3 25 2 53 3 6 1 SR Model G1 BC 1 5 1 8 0 0 8 7 26 4 55 8 8 6 W in Manufacturer 0 0 0 8 33 7 8 14 4 23 3 SR Model G7 0 0 0 9 3 4 7 8 14 5 24 0 0 7 SR Model G1 BC 0 0 0 9 3 7 8 6 16 1 26 2 2 9 308 Win Drop inches 308 Win Drop inches G1 Model with BC Correction Manufacturer s Data G7 Model Manufacturer s Data 100 200 300 400 100 200 300 400 www ttfsapp co
6. C ballistic coefficient and ambient weather conditions compensation yielding accurate bullet drop and wind drift solutions For ease of use Shooter s Reference has a built in database of over 2 000 cartridges from Barnes Buffalo Bore Eley Federal Premium Fiocchi Hornady Norma USA Nosler PMC Remington Weatherby and Winchester In addition the user can manually enter the required input parameters such as muzzle velocity and bullet weight Additional tools are included that aid sight in calculations at the range estimating the distance to a target and performing mils and moa calculations Both imperial and metric units are supported Comments complaints suggestions and questions are appreciated COPYRIGHT 2014 THIS TIME FOR SURE APPS LLC Contact Us support Ottfsapps com Sea rch find your cartridge s specs in the built in database Cartridge Database In order to set up the ballistics calculator there are a few parameters you need to know about your cartridge We have included a database of over 2 600 popular rifle and handgun Sed 10 a cartridges that can be searched simply by tapping the search boxes on the search page Tap the products box to see the firearm type list of cartridges that match your criteria and to choose one Note that a maximum of 100 products can be displayed The best way to avoid that limit is to choose a cartridge SHOOTER S REFERENCE V3 Ce
7. Muzzle 4830 Use lookup page to automatically enter ballistics data if available CROWN MOLDING And it s Any angle Any place Calculate FREE CALCULATOR once and measure twice setu D setup model parameters Model Setup Cartridge and Bullet Parameters These parameters describe the cartridge and bullet bullet caliber Required inches or mm depending common usage bullet weight Required always in grains ballistic coefficient Only required if use bc box is checked Default is to not use BC in ballistics model yields best results Can be applied to any of the bullet models but most manufacturers only specify a G1 BC bullet model Required G7 default G7 works best for low drag bullets See page 30 Standard Bullet Models for more information SHOOTER S REFERENCE V3 setup cartridge and bullet parameters bullet caliber bullet bullet in or mm weight gr bullet bc model 5 G2 muzzle muzzle energy b velocity fps ft lbs adiu G5 ambient conditions wind speed wind direction elevation deg ft so temperature humidy pressure deg F rh in Hg firearm setup scope height zero dist units in yds check for setu D setup model parameters Model Setup continued Cartridge and Bullet Parameters continued use bc Not required or recommended If checked ballistics model applies BC to selected bullet models drag coefficient muzzle velocity Requi
8. Revised August 2014 3 a Diedra V rau index TOPIC SUMMARY PAGE Introduction Cartridge Database e search e specs Ballistics Model e setup e solve e hold e table Other Tools e sight in e range e convert e safety rules Appendix e model internals e model performance Summary of Shooter s Reference V3 and what s new How to use the cartridge database Look up a cartridge by firearm type caliber use manufacturer View the specs of a selected cartridge How to use the ballistics calculator Set up cartridge ambient range and firearm parameters Calculate solution at distance bearing and inclination View mil scope display hold for calculated solution View range table with drop and drift corrections A collection of other handy tools and calculators Dial in your scope on the range Determine the range of an object of known size MOA Mils converter Col Jeff Cooper s rules four rules Other stuff you might want to know How the ballistics model works Comparison of model vs manufacturers published ballistics 3 16 17 18 19 20 21 23 33 1141919 uction getting started Shooter s Reference V3 is a ballistics calculator for sports shooting enthusiasts that features a classical physics based projectile motion model cartridge database and several other useful tools The V3 ballistics model supports G1 and G7 drag models as well as many others B
9. UZZLE OF A FIREARM POINT loaded ANYTHING YOU ARE NOT WILLING TO DESTROY Never let the muzzle KEEP YOUR FINGER OFF THE TRIGGER UNTIL YOUR SIGHTS ARE ON THE TARGET of a firearm point at SURE OF YOUR TARGET anything you are not willing to destroy THE IMPORTANCE OF THESE RULES CAN NOT BE STRESSED ENOUGH THE MOST IMPORTANT SAFETY FEATURE WHEN Keep your fi poisi off HANDLING A FIREARM IS THE ONE BETWEEN YOUR EARS NOT THE ONES ON THE FIREARM the triaaer iinless gee FASTENER REFERENCE And it s Don t know the size of that screw Or FREE REFERENCE a pan head from a cheese head APPENDIX Model internals Model performance model Shooter s Reference s ballistics model is based on Newtonian physics This section describes the inner workings of the model in mathematical terms Basic knowledge of physics and calculus is required to understand the model but is not a prerequisite for using the application Several good books available as well as Wikipedia s articles on external ballistics and related topics as well as many other Internet sources Our preferred source is Bryan Litz s excellent book Litz Bryan 2011 Applied Ballistics for Long Range Shooting 2 edition Cedar Springs MI Applied Ballistics LLC The ballistics model can be divided into three functional blocks Ambient Conditions Firearm Setup Projectile Motion Simulation Ambient Conditions T
10. dry air adiabatic index VARIABLE DESCRIPTION VARIABLE DESCRIPTION Farag Carag CG1cD Ay DA Vy t X t Y t Xh ty la calculation Interval distance calculation interval time force vector mass acceleration vector diameter of bullet drag force drag coefficient drag coefficient of G1 std model acceleration at time t in x or y velocity at time t velocity at time t in x or y position at time t horizontal distance time of flight in a vacuum actual time of flight model internals imow it works Standard Bullet Models MODEL DESCRIPTION Shooter s Reference allows the user to select G1 Ingalls Flatbase 2 caliber blunt ogive various standard models that are used to calculate nose Generally used by manufactures bullet drag By choosing the model that best fits your to express BC bullet you can improved the accuracy of the results G2 Aberdeen J projectile Shooter s Reference continuously adjusts drag based on the instantaneous velocity of the bullet G5 Short 7 5 boat tail 6 19 caliber based on the selected bullet shape model tangent ogive nose G6 Flatbase 6 caliber secant ogive nose The descriptions of the bullet models in the table to the right refer to the terms blunt ogive secant ogive with and tangent ogive These describe the shape of the bullet s nose and date back to nose cone designs for rockets G7 Long 7 5 boat tail 10 caliber tangen
11. e local atmospheric pressure can not be determined an approximation can be made based on altitude and either actual nearby or standard sea level pressure h p poe Vis The partial pressure of dry air can be determined by simple subtraction P Pwv The density of a mixture of dry air and water follows Pary X Mary Pwo X Mwy Phumid 7 RxT The speed of sound varies with air density and is given by model internals imow it works Firearm Setup Bore angle is the barrel cant that results from the difference between the line of sight to the target what you see through the scope or sights and the launch angle required to be on target at the zero distance on flat ground Shooter s Reference allows the user to choose an arbitrary zero distance Line of Sight 08 Bore Angle Angle Exaggerated For Illustration Purposes Source http en wikipedia org wiki Rifleman s rule Most manufacturers ballistics tables assume a height of 1 5 inches but chances are that your sights or scope are not mounted at that height This is a significant source of error The centerline to centerline height of the sights or scope above the barrel is required to calculate the bore angle This measurement Is critical and should be taken with care A zero distance that is close to the target range is recommended For example when targets are likely to be around 75 yards away set the zero distance to 75 yards
12. here are three factors that are important to calculating an accurate trajectory air density the speed of sound and crosswind speed Air density can be calculated one of two ways by the model The preferred method is to use temperature pressure and humidity at the shooter s location Alternatively the model can use elevation and sea level temperature pressure and humidity or their approximation In reality for hunting distances out to 500 yards air density is a very small factor in bullet drop or drift typically on the order of tenths of an inch By comparison we see several inches of variation when comparing trajectories generated by utilizing the G7 model instead of the G1 BC model see comparisons in Appendix model internals how it works To determine air density from temperature pressure and humidity we employ the following equations First we calculate the saturation pressure for water vapor from a rather complicated magical formula that uses temperature only 77 43540 0057 522 T Psat Next we calculate the partial pressure of the water vapor from the relative humidity and the saturation pressure This is a very small number on the order of 1 2 of the total atmospheric pressure RH 100 X Dsat Pus Before we calculate the partial pressure of dry air we need to know the local atmospheric pressure This can be measured directly or obtained from your favorite weather website If th
13. ination yds deg angle deg 325 M solve solution solution correction inches moa mils drop 9 4 U2 7 U0 8 drift 9 0 L2 6 L0 8 kinetic energy ft lb 3286 velocity fps 2433 laser los intercept yds 30 3 laser position on target in 14 6 SHIP OF FOOLS Play the classic dice game of Ship Captain and Crew And it s FREE solve enter target data and solve model The inclination angle is the angle of the target relative to the shooter A 0 inclination is horizontal flat ground Positive inclination angles indicate an uphill shot while negative inclination angles indicate a downhill shot Please refer to SO lve Wikipedia for an explanation of the Rifleman s Rule SHOOTER S REFERENCE V3 target parameters distance bearing inclination yds deg angle deg 325 EM solution solution correction inches mils drop 9 4 U2 7 U0 8 drift 9 0 L2 6 L0 8 RH Horizontal Distance kinetic energy ft lb 3286 Source http en wikipedia org wiki Rifleman s rule velocity fps 2433 laser los intercept yds 30 3 laser position on target in 14 6 SHIP OF FOOLS And it s Play the classic dice game of Ship Captain and Crew FREE solve enter target data and solve model The bearing is the compass bearing of the target Wind Target Direction Bearing 315 45 Target Bearing 225 Tip Target bearing is the direction in which the firearm is po
14. inting Wind direction is where the wind is blowing from meteorological convention SHOOTER S REFERENCE V3 target parameters distance bearing inclination yds deg angle deg s 8 f MEM solution solution correction inches mils drop drift kinetic energy ft lb velocity fps laser los intercept yds laser position on target in SHIP OF FOOLS Play the classic dice game of Ship Captain and Crew solve enter target data and solve model Click the solve button to calculate the solution Drop and drift are displayed in length units as well as mils and U and D preceding a number refer to up and down while L and R preceding a number refer to left and right sight adjustments For example in the screenshot to the right the sights should be adjusted up 2 7 MOA or 0 8 mils to account for bullet drop 2 6 MOA or 0 4 mils left must be dialed in to account for wind drift The kinetic energy and bullet velocity at the target distance are also displayed Kinetic energy is displayed in either ft lb or Joules Velocity is displayed in feet per second fps or meters per second mps Bore Laser Sight The laser bore sight solution displays the two key numbers required to sight in a firearm at a desired zero distance when using a bore laser light such as the S TELITE Mag Laser Boresighters A The laser LOS intercept is the distance at which
15. let model that most closely matches the bullet in use be chosen BC s are not constant with speed although manufacturers quote a single BC typically based on the G1 model in their cartridge specifications Using the manufacturer s BC introduces a systemic error and results in larger errors The Appendix shows model results for three common cartridges with and without BC compensation For modern low drag bullets the G7 model without BC compensation provides the best results The ballistics model implements a table of drag coefficients for each of the supported bullet models developed by the Army Ballistics Research Lab These are discussed in the bullet models section A new drag is calculated for each trajectory point based on the bullet s velocity at that point The two equations for calculating drag are OpXvV Carag X A Farag 7 Coicp X m EI If BC is used model internals how it works The ballistics model simulates the path of the projectile or bullet by repeatedly calculating Its drag velocity acceleration and position at Intervals of either 0 5 yards or meters depending on whether Imperial or metric units are selected The initial conditions are determined by the muzzle velocity and the launch angle The launch angle is determined by the inclination angle to the target and the bore angle of the zeroed firearm The model performs calculations based on units of time required to
16. listics Tutorial ARL TR 1124 The full text may be downloaded from http www dtic mil dtic tr fultext u2 a31 7305 pdf The amount of drift requires the calculation of the perpendicular wind speed the actual time of flight and the time of flight in a vacuum The time of flight in a vacuum is simply the time to travel the horizontal distance at the muzzle velocity since there is no drag to slow the projectile s velocity while in flight Xh v Vo The wind drift is calculated with the following equation Vw X tg ty model internals how it works Kinetic Energy Kinetic energy is calculated at the target range While kinetic energy is a good indicator of a bullet s ability to stop and or kill game It is not the only factor The user of this program should consult the manufacturer s recommendations for specific game A small bullet with high kinetic energy does not perform the same as a large bullet with the same kinetic energy Kinetic energy is calculated as follows m x v E 2 model internals imow it RH Pp Po Psat Pwy Pary p humid temperature relative humidity barometric pressure sea level barometric pressure vapor saturation pressure partial pressure of water vapor partial pressure of dry air density of humid air perpendicular cross wind speed elevation height of the atmosphere speed of sound universal gas constant molar mass of water vapor molar mass of
17. nter Fire Rifle 338 Lapua Magnum The parameters required by the ballistics calculator are automatically loaded into the Setup page when a product is tap to select selected The following parameters are extracted manufacturer Bullet diameter Winchester Bullet weight Ballistic coefficient optional not required Winchester GM338LM Muzzle velocity 1 Use lookup page to automatically enter ballistics data if available Muzzle energy not used but displayed CROWN MOLDING it s e ee Any angle Any place Calculate FREE CALCULATOR once and measure twice Specs view manufacture s data and description Cartridge Specs When a cartridge is selected from the database a summary of the its specifications is displayed on the Specs page The S e CS specs are from the manufacturer and are subject to change o SHOOTER S REFERENCE V3 Typically the following specifications are available manufacturer s specs Manufacturer Winchester Firearm Type Center Fire Rifle Manufacturer product line and part number Part Number GM338LM Cartridge and bullet description Cartridge 338 Lapua Magnum Typical licati Cartridge metric 8 6x70mm ypical application Bullet BTHP Product Line Sierra MatchKing Bullet weight and ballistic coefficient Application Competition Muzzle velocity Bullet Weight gr 250 0 587 Muzzle energy Velocity Muzzle 2950 Energy
18. re selected sight picture values are displayed in meters SHOOTER S REF V3 And it s Ballistics calculator for the REE shooting sports F ta b view drop and drift correction table Drop and Drift Table Once a solution is found the table page displays the drop and drift solution from 50 to 500 yards or meters at 5 yard or meter ta D increments at a zero degree inclination angle SHOOTER S REFERENCE V3 TT i dist drop drop drop drift drift drift U and D preceding a number refer to up and down while L vds in mils moa in mils moa and preceding a number refer to left and right sight 185 06 U01 U03 29 104 L15 adjustments 0 2 UO0 UO 32 LOS 116 35 LOS L116 C i i M I I 3 9 4 3 E 9 C Me 2 9 U0 4 59 L2 1 SIX SIGMA And it s Statistical tools for the six sigma FREE practitioner SIG nt In sight in your rifle at the range Sighting in on the Range The sight in page provides a simple non model method of zeroing a firearm on the range target distance Required in yards or meters vertical adjustment gt Required in inches or centimeters gt The vertical distance to move the impact point Enter a positive value to move the impact point up a negative value to move the impact point down horizontal adjustment gt Required in inches or centimeters
19. red in fps or mps muzzle energy Displayed for information only in ft lbs or Joules SHOOTER S REFERENCE V3 setup cartridge and bullet parameters bullet caliber bullet bullet in or mm weight gr bullet bc model 5 G2 muzzle muzzle energy b velocity fps ft lbs 2950 ambient conditions wind speed wind direction elevation deg ft so temperature humidy pressure deg F rh in Hg firearm setup scope height zero dist units in yds check for nm setu D setup model parameters Model Setup continued Ambient Conditions Entering ambient conditions allow Shooter s Reference to calculate wind drift corrections as well as air density compensation U S Army Standard Metro conditions are the default wind speed Optional in mph or kph wind direction Optional in degrees using meteorological convention see illustration on page 13 elevation Optional in feet or meters above sea level If zero temperature humidity and pressure are used to calculate air density most accurate method If non zero then altitude is used to calculate air density better than no air density correction SHOOTER S REFERENCE V3 setup cartridge and bullet parameters bullet caliber bullet bullet in or mm weight gr bullet bc model 5 G2 muzzle muzzle energy b velocity fps ft lbs adiu G5 ambient conditions wind speed wind direction elevation deg ft so tempera
20. t Default ogive nose Best model for low drag Model bullets Some manufacturers provide G7 BC s in addition to G1 BC s G8 Flatbase 10 caliber secant ogive More information on nose cone designs is available nose on Wikipedia GL Blunt lead nose http en wikipedia org wiki Nose cone design Source http en wikipedia org wiki External ballistics model mm Manufacturers typically provide a BC ballistics coefficient that is based on the G1 model Some 3 have also started providing G7 based BC s 3 However best results are achieved without using BC compensation because BC s vary with velocity s 0 600 e 914 The G1 and GL models will yield very similar results _ typically within 0 5 inches 1 3 cm of drop at 500 G1 G7 G1 GL G7 37 yards 457m The G2 G5 G6 G7 and G8 models also yield similar results Since most long range shooters are using very low drag boat tails for best performance the G7 model yields the best results Cd vs Velocity mach Bullet Shape and Recommended Model Results of comparisons of manufacturer s data compared with the model solutions with and without BC compensation are provided for the Winchester 308 Winchester 338 Lapua Magnum and the Winchester 300 Magnum model performance data winchester magnum V fps 300 Win Mag Winchester GM300WM Manufacturer s Data vs Shooter s Ref Model Distance
21. t Determines range table increment display SHOOTER S REFERENCE V3 target range estimator actual size in solve solution scope size mils est distance yds 500 size mils dist yds scope units mils 3 1 3 8 moa 39 table increment 4 0 a 4 1 4 2 1 10th 43 BE SURE OF YOUR TARGET 541 526 500 488 476 465 conve rt convert distances to mils and moa Converting Mils or MOA The convert page provides a simple calculator to determine the value of Mils MOAs at a given distance distance gt Required in yards or meters gt The target distance The value of both a Mil and MOA or quarter fractions is displayed in inches or centimeters SHOOTER S REFERENCE V3 convert mil moa converter distance yds 100 solution unit fraction value of 1 JA V VA mil in 36 27 18 0 9 moa in 10 08 05 03 1 Enter distance calculate value of a moa or mil Unit fraction is fraction of moa or mil KEEP YOUR FINGER OFF THE TRIGGER UNTIL YOUR SIGHTS ARE ON THE TARGET safety ru les read them learn them live them Lt Col Jeff Cooper USMC founder of Gunsite Academy author columnist professor WW II and Korean War combat SHOOTER S REFERENCE V3 veteran and innovator of the Modern Technique of the Pistol satety rules had four simple safety rules ALL FIREARMS ARE ALWAYS LOADED All firearms are always NEVER LET THE M
22. tance the bore sight calculator requires the ballistics of the cartridge in use and velocity fps the mounting height of the scope or sights The cartridge ballistic specs can be manually entered in the setup page laser los intercept yds or by selecting a cartridge in the search page Consult laser position on target in your laser bore sight manufacturer s user s manual for instructions specific to your model a kinetic energy ft lb SHIP OF FOOLS Play the classic dice game of Ship Captain and Crew hold sight picture Mil Dot Sight Picture Once a solution is found the hold page displays the hold position required to be on target at the distance bearing and a C inclination angle entered on the Solve page Holding the firearm such that the target is in the position indicated by the green dot will place the shot on the target target parameters ambient conditions distance yds wind speed mph 15 325 The vertical axis is labeled in half mil dot increments with the on RC it Miao Ke Liao EM e Ele target distances corresponding to that vertical hold The 0 210 horizontal axis is also labeled in half mil dot increments with the distances corresponding to wind drift SHOOTER S REFERENCE V3 bearing deg 0 For example a 350 yard shot would require a vertical hold of just under 1 mil 352 yards for drop and about 0 7 mils 0 7 x 500 yards for wind drift When metric units a
23. the bore laser line and the line of sight cross It is displayed in yards or meters If you place a target at this distance the laser dot on the target should be right in the center of the scope or on the front sight SHOOTER S REFERENCE V3 target parameters distance bearing inclination yds deg angle deg 325 M solve solution solution correction inches moa mils drop 9 4 U2 7 U0 8 drift 9 0 L2 6 L0 8 3286 2433 kinetic energy ft lb velocity fps laser los intercept yds 30 3 laser position on target in 14 6 SHIP OF FOOLS Play the classic dice game of Ship Captain and Crew And it s FREE solve enter target data and solve model The laser position on target is the distance from the sight position to the laser dot on the target required to achieve the SHOOTER S REFERENCE V3 desired zero distance The target distance is the value entered for distance under target parameters S lve 2 0 Bore Laser Sighting Bore Laser Line target parameters Laser LOS distance bearing inclination intercept point d d l 5 ang e eg Laser dot above crosshair by 1 inch with target at 50 yards y zs do go EET 1 0 solution Laser dot below crosshair by 1 inch with target at 10 yards me Scope mounted 1 5 inches center to center above bore at 200 ya e NS solution correction eM inches moa mils 50 100 150 drop drift Tip In addition to the target dis
24. travel the model distance interval dx Vx 0 dt The initial velocity is the muzzle velocity V o Vmuzzle oince the projectile is launched at an angle at a minimum the bore angle on flat ground it is necessary to determine its velocity in both the x and y axes In addition the forces of gravity and drag act differently in both axes so those must also be treated separately The initial velocities in the x and y axes are given Dy Vx 0 Vo X cos 0 Vy o Wo X sin 0 Acceleration is given by the general vector formula F F m a Acceleration deceleration in this case can be approximated as follows for each axis Farag Farag m and G model internals imow it works Given velocity acceleration and time a new position can be calculated Ay gt X t 1 X t Ux t x dt p x dt Ay Y t 1 Y t Vy t x dt PI x dt New velocities are similarly updated Vy t 1 Vx t ax X dt Vy t 1 Vy t X at U t1 LG Vy t41 oince the projectile is now moving more slowly the time to travel to the next computation point also needs to be recalculated dx Vx t 1 dt The process repeats until the drop and drift table is completed and the target distance reached Wind Drift Wind drift is calculate using the Army Ballistics Lab method described in Leupold Herbert A October 1996 Wind Drift of Projectiles A Bal
25. ture humidy pressure deg F rh in Hg firearm setup scope height zero dist units in yds check for setu D setup model parameters Model Setup continued Ambient Conditions continued temperature Optional in degrees Fahrenheit or Celsius humidity Optional in RH percent pressure Optional in inches of Mercury or hectoPascals Tip If exact ambient conditions are not available a good guess at temperature and humidity while leaving the pressure at the default value will improve the ballistic model s results SHOOTER S REFERENCE V3 setup cartridge and bullet parameters bullet caliber bullet bullet in or mm weight gr bullet bc model 5 G2 muzzle muzzle energy bie G5 velocity fps ft lbs G6 2950 ambient conditions wind speed wind direction elevation deg ft so temperature humidy pressure deg F rh in Hg firearm setup scope height zero dist units in yds check for nm setu D setup model parameters Model Setup continued Firearm Setup The model uses the scope mounting height and the zero distance to calculate the bore angle of the firearm relative to the line of sight The centerline to centerline height of the scope relative to the barrel is critical to the accuracy of the model scope height The centerline to centerline height of the scope or sights to the barrel Required in inches or millimeters zero distance Required in yards
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