1 BALLISTIX II A FULL FEATURED BALLISTICS PROGRAM FOR THE HUNTER, TARGET SHOOTER AND RE-LOADER. MILE 300 COMPUTER SERVICES Author: John R. Saunders Copyright (c) 1989, 1990, 1991, 1992 Mile 300 Computer Services. All rights reserved. 2 TABLE OF CONTENTS Welcome to BALLISTIX II pg 3 Starting BALLISTIX II pg 4 The Environmental Variables Screen pg 5 The Load Variables Screen pg 6 The Ballistics Table Screen pg 7 The Main Menu pg 8 The Parameters Screen pg 9 Sending the Ballistics Table to a printer pg 10 Sending the Ballistics Table to an ASCII file pg 10 Free Recoil pg 10 Bullet Terminal Performance pg 10 The Load Database pg 11 The Database Menu pg 12 Using the Load Database pg 13 The Group Statistics Calculator pg 14 The Zero Change Calculator pg 15 Maximum Point-blank Range pg 17 Charge Calculator pg 18 Ballistic Coefficient Calculator pg 20 Graphs pg 21 Target Lead Calculator pg 21 Compare Two Loads pg 22 Shell out to DOS pg 22 The Rifle Database pg 22 Quitting BALLISTIX II pg 22 3 WELCOME TO BALLISTIX II The magic is gone from external ballistics calculations for- ever thanks to BALLISTIX II an easy and intuitive program for IBM PC/XT/AT and compatible computers. No more sitting at a desk with a calculator and a re-loading manual to determine where your bullet is going and what it is doing when it gets there. BALLISTIX II will make ballistic calculations so quick and easy that you will learn more in less time and may even become a better shooter to boot. Ballistics calculations are no stranger to computers. The first computers built in the United States were put to work for the defense department to generate shooting tables for the navy's big guns. That same power is now brought to the Personal Computer in the form of BALLISTIX II. BALLISTIX II has taken approximately 400 hours of programming and debugging to reach this point, and has migrated from a simple ballistics table generation utility that I used in my hobby, to a full featured tool for serious hunters, re-loaders, and target shooters. There is not much more that I could put into the program, and I hope that you will find it useful. Use and enjoy. Though BALLISTIX II is being distributed via the "shareware" route, it is not in the public domain. All rights are reserved by Mile 300 Computer Services. You may copy and transfer the program as you wish as long as this manual and all other files on the distribution disk are included. You may not disassemble, decompile or alter the code without consent of Mile 300 Computer Services. The source code and an extended licence are available from Mile 300 Computer Services should you wish to experiment with the code. Any changes in the code must not remove the copyright and authorship acknowledgements. 4 STARTING BALLISTIX II The files that are included in the ZIPped file that you have decompressed are as follows: BALLIST2.EXE The program itself. BALLIST2.DOC This manual. BALLIST.DTA A sample load database file. RIFLE.DBR A sample rifle database file. START.UP The start up data needed. To start BALLISTIX II, just type BALLIST2 and the program will run. Ensure that all of the other files are in the same directory as the program. BALLISTIX II can be started with one of three command line switches: BALLIST -D Starts BALLISTIX II and places you immediately into the load database. BALLIST -T Starts BALLISTIX II and skips the variable input screens. BALLIST -P Starts BALLISTIX II and immediately shows you the initial and calculated parameters used by the program. If you don't enter any switch, BALLISTIX II will show you several screens on start up where you may enter load information. All of the screens are described later in the text. That is about all you need to know to start into doing serious ballistics calculations with BALLISTIX II. I'm sorry, but it's just not that complicated anymore. I suggest you start BALLISTIX II now, and actually use the program while thumbing through the manual. After that, you probably won't need this manual again. The progam is fairly intuitive. 5 THE ENVIRONMENT VARIABLES SCREEN BALLISTIX II requires certain values to be entered by you in order to model the atmosphere the the projectile will be moving through. This enables the program to generate an extremely accurate ballistics table. The atmosphere is critical when any ballistics tables are generated, as the movement of the air mass along with it's density dictate the position in space and velocity of a projectile at any time. In order to make BALLISTIX II as accurate as possible without becoming mired in miniscule atmospheric modeling, several general variables are used to create the needed atmospheric model. These are: ALTITUDE - enter this value in feet above sea-level. AMBIENT AIR TEMPERATURE - degrees Fahrenheit. AIR PRESSURE - inches of mercury. WIND SPEED - in miles per hour. WIND ANGLE TO LINE OF BORE - at 0ø the wind is blowing down the barrel, at 180ø it is blowing from the rear, 90ø is from the right, and 270ø is from the left. ELEVATION ANGLE - in degrees, the angle that the barrel is above/below horizontal. TABLE STEP - the range increment (in yards) that BALLISTIX II will use in the ballistics table. The value that is being edited is highlighted, and you can use the up/down arrow keys to move between variables. To accept a variable use an arrow key to select another variable or strike . When you are finished strike to move the the next screen. 6 THE LOAD VARIABLES SCREEN BALLISTIX II requires that you enter information concerning the load in order to properly calculate the ballistics table. In the Load Variables screen you are given the opportunity to enter the required information. Moving around the screen and accepting an edited values is exactly the same as in the Environment screen described previously. The values that BALLISTIX II requires are these: MUZZLE VELOCITY - the speed, in feet/second that the projectile is traveling at the instant that it leaves the barrel. You can obtain this from a reloading manual or, preferably, from a chronograph or ballistic pendulum. BULLET DIAMETER - in inches. BALLISTIC COEFFICIENT - this is the ratio of the calculated drag of the projectile to a "standard bullet". Generally flat and round nose bullets have lower BC's than long, pointed bullets. The higher the ballistic coeficient, the easier the bullet moves through the air, the higher the retained velocity. You can obtain the BC from a loading manual for that make of bullet, or you can let BALLISTIX II calculate one for you. <> BULLET WEIGHT - in grains. BARREL LENGTH - the length of the barrel from the beginning of the chamber to the muzzle. You can generally measure from the muzzle to the receiver ring and add about 3/4 of an inch. BARREL LENGTH FROM MANUAL - if you are using a reloading manual as the source of your muzzle velocity, you must enter the barrel length that the manufacturer used in obtaining that muzzle velocity. If you used a chronograph or ballistic pendulum, make both barrel lengths identical. SIGHT HEIGHT - the distance between the center of the scope or the plane of the iron sights and the center of the bore in inches. ZERO RANGE - the distance that the rifle is to be zeroed at in yards. CARTRIDGE NAME - a name that is to be used to identify the load. 7 THE BALLISTICS TABLE SCREEN BALLISTIX II generates a comprehensive ballistics table that is displayed after all the required variables have been entered in the Environment and Load Variable screens. BALLISTIX II uses these variables to model the atmosphere that the bullet will be traveling in, and the bullet itself to provide the most accurate information available to you. At the top of the Ballistics Table screen the name of the current load and it's bullet weight are displayed. These are the values that BALLISTIX II uses in all of the remaining program screens to identify the current load. In the Ballistics Table screen, several different parameters are displayed in table format with the range down the left side, from 0 yards to 10 times the value that you chose for STEP TABLE in the Environment Variable screen. Normally this value will be 500 yards, but can be altered by you to give more usefull data on lower powered cartridges. Across the top from left to right are the parameters that are displayed in the Ballistics Table screen. These are: VELOCITY - the velocity remaining at each range increment. ENERGY - the terminal energy at each range increment. TOF - the time of flight to that range. DROP - how far gravity has pulled the load. PATH - the position of the bullet above/below the line- of-sight DRIFT - the position of the bullet left/right of the line-of-sight due to wind drift The velocity and energy values are rounded to the nearest foot/second and foot/pound respectively as a display to 1 or 2 decimal places would be space consuming and would not enhance the accuracy. The time of flight is rounded to 3 decimal places, and the remainder of the parameters are shown to 2 decimal places. This give optimal performance withoug getting caught up in needless accuracy. At the bottom of the Ballistics Table screen is a menu containing several choices. The Ballistics Table screen is the main screen of BALLISTIX II, and all other segments of the program are entered via the Ballistics Table screen. The selections have been given names short enough to fit the menu box, but you can get an expanded explanation of the selections by striking F1. This shows a help screen that gives the menu selections and an explanation of what each segment of the program does. 8 THE MAIN MENU As described previously, the main menu displayed at the bottom of the Ballistics Table Screen. In order to select from the menu, simply strike the key that coresponds with the highlighted letter in the selection name in the menu box. The selections are: E Environment Edit/view the environment variables. L LOAD Edit/view the load variables. P Parameters View the initial/calculated load parameters. P Print Send a ballistics table to the printer. F File Send a ballistics table to an ASCII file. O Recoil Calculate the free recoil of the rifle/load and display bullet terminal performance information. D Database Use the load database. H Charge Calculate an initial load of IMR powder. U Groups Use the group statistics calculator. Z Zero Calculate the number of scope clicks needed to change zero for your rifle/load. B PBR Calculate maximum point-blank-range. C Coef Calculate a ballistic coefficient. G Graph Display a graph of path, drop and wind- drift. A Lead Calculate how much to lead a moving target. M Compare Compare the ballistics of two loads. S System Shell out to DOS. I Rifle Create/display rifle information attached to the current load. Q Quit Exit to DOS. Each segment of the program will be described in detail later in the manual. 9 THE PARAMETERS SCREEN In order to display the Parameters screen, strike P when in the main menu. BALLISTIX II calculates changes to two of the variables that have been entered in the Load screen according to the model of the atmosphere that has been described in the Environment screen. The two variables that are affected are the muzzle velocity and the ballistic coefficient. Muzzle velocity is directly affected by differences in barrel length between the barrel being used and the one used in a reloading manual to obtain a velocity. Also, muzzle velocity is altered according to the headwind component of the wind. The ballistic coefficient is affected by air density. Altitude, ambient air temperature and air pressure all affect the density of the atmosphere and therefore, the ballistic coefficient. The Parameters screen shows some of the calculated values that BALLISTIX II uses along with what was entered so that you can see the changes. To re-display the Ballistics Table, hit any key when the Parameters screen is in view, or to print the parameters, set up your printer and strike P. If your printer is not ready, or if BALLISTIX cannot communicate with your printer, you will receive an error message. Correct the problem and hit any key, or to exit the Parameters screen. 10 SENDING THE BALLISTICS TABLE TO A LINE PRINTER If you should want a printout of the ballistics table all that you need to do is set up your printer and strike the R when in the Ballistics Table screen. If your printer is not ready or if BALLISTIX cannot communicate with you printer, you will receive an error message. Correct the problem and hit any key to continue, or to exit to the Ballistics Table screen. SENDING THE BALLISTICS TABLE TO AN ASCII FILE You can store the ballistics table to an ASCII file on disk by striking the F key when in the Ballistics Table screen. You will be prompted for a filename. Type in the name you wish and hit . The ballistics table will be store in a pure ASCII file with the extension of .LOG in the current directory. You may retrieve this with a word processor, or print it through DOS services at a later date if you wish. CALCULATING FREE RECOIL To enter the Free Recoil calculator strike O when in the Ballistics Table. Free recoil of any weapon system is a function of the weight of the system, the weight of everything that comes out of the barrel, and the velocity of the projectile. When entering this segment of the program, you are prompted for the weight of the powder charge in grains and the weight of the rifle in pounds. BALLISTIX II then calculates a value for free recoil in foot/pounds and displays this on screen. BULLET TERMINAL PERFORMANCE When the Free Recoil Calculator is entered BALLISTIX II calculates and displays two bullet performance values. These are Momentum and Optimum Game Weight. Neither of these is one of the standard values that a shooter looks at normally, but both have their merits. The momentum value is a direct indication of the penetration power of the bullet, and the Optimum Game Weight value is good for comparison and is a value of how large an animal should be considered maximum for any load. Of the two the momentum number is the most useful. The OGW value is given for comparison only. 11 THE LOAD DATABASE To enter the Load Database, strike D when in the Ballistics Table screen. The load database contained in BALLISTIX II is designed to provide the program with all of the necessary information to generate the ballistics tables. Therefore, all of the information that is entered in the Environment and Load variable screens is contained for each load in the Load Database. When the database is first entered, you are prompted to enter the name of the database file that you wish to use. The available database files that are in the current directory are listed at the bottom of the screen in the DATABASE FILES AVAILABLE section. All you need to do is type in the filename of the file that you wish to use and hit . All database files have the extension .DTA therefore the extension need not be entered. Once the filename has been given to the program, BALLISTIX II enters the main database screen and displays the names of the loads in the database along with the bullet weights on screen 10 at a time. AT the bottom is the name of the current file (the file being used) and the total number of records in that file. Above this is the DATABASE MENU which offers you several functions. MOVING AROUND IN THE DATABASE The database is broken down into pages and records. A page is comprised of 10 records. When the database is first entered Page 1 is shown. To see the next page you can either hit PgDn, the DnArrow, or hit N for NEXT. To view the previous page hit PgUp, the UpArrow or hit P for Previous. To move to the last page hit End and to move to the first page hit Home. 12 THE DATABASE MENU At the bottom of the database screen is displayed the Database Menu. This is used in the same fashion as the main menu of the program. In order to select a database function strike the key corresponding to the highlighted letter in the menu selection. Here is a brief synopsis of the database functions: N Next Move to the next page in the database. P Previous Move to the previous page in the database. S Select Transfer a load from the database to the main program to work with. D Delete Delete a load from the database. A Add New Create a new load to add to the database. C Add Current Add the load that was displayed in the Ballistics Table screen to the database. V View View the stored information for a load. X Exit Return to the Ballistics Table screen. (A list of the command keys and their function can be gotten while the Database menu is on screen by hitting the F1 key.) To keep things as simple as possible while keeping some utility to the database, higher functions such as sorting etc. have not been included. The function of this database is such that a shooter can keep track of any of his loads easily. Should the user wish to store his reloading manuals electronically, all that needs doing is to set up a database file named HORNADY.DTA (or whatever the company) and enter one representative load for each caliber. The information is then in the computer available to BALLISTIX II for comparison or use in the future. The author keeps the Hornady, Sierra, Speer and Nosler loads stored in this fashion and finds that it makes some things easier. 13 USING THE LOAD DATABASE SELECTING, DELETING OR VIEWING A LOAD All of the above functions of the database are accessed in exactly the same fashion. We will use load selection as an example. To select a load, when the page containing the desired load is on screen strike the S key for select. A box will appear asking for the number of the load. You will notice that in any page, all the loads are numbered from 1 to 10 (if there are 10 loads on that page). All that is needed is for you to type in the number of the load that you wishe to use and hit . The load is retreived and the program returns to the Ballistics Table screen for further work. Deleting or Viewing a load is the same. If the you choose delete you will be prompted for the number of the load. That load is then deleted from the database. If you choose to view a load, the stored information for that load is displayed on screen. ADDING THE CURRENT LOAD If you wish to store the load that you are working with in the database you must first enter the database by striking D when in the Ballistics Table screen then provide the filename of the database file that you wishe to store the load in. When the database menu appears, you need only strike the C key. The load is stored. Now strike X to return to the Ballistics Table screen. CREATING A NEW LOAD TO ADD TO THE DATABASE If you are in the database and wish to create a new load to be added to the database, strike A. You will be shown the Environment and Load variable screens for entering information to be stored. When you are done you will be returned to the database. EXITING THE DATABASE To exit the database, you need only strike X when the Database Menu is visible. 14 THE GROUP STATISTICS CALCULATOR To enter the Group Statistics Calculator, strike U when in the Ballistics Table. The group statistics calculator has been designed so that you can determine the exact center of groups, and see how the center changes as the barrel heats up etc. This can be useful to both the hunter and target shooter though most hunters will not shoot enough to cause the barrel to heat much. Hunters can though see if a group has migrated from season to season which may mean that there is some uneven pressure on the barrel from the stock. When you first enter the statistics calculator you are asked how many shots there are in the group. The calculator will accept up to 10 shots in a group. Should you decide that you do not wish to continue, type in '99' and . This will take you back to the Ballistics Table screen. If you have entered a number of shots for the load the next thing that you will see is the Shot Information Entry screen. In this section you will enter the position of each shot. For the statistics calculator to be usefull other than to determine the final center of the group, you must have kept track of each shot in the group and enter them in order from shot 1 to shot n. The position of each shot is entered as a value either left (-) or right (+) of center and either below (-) or above (+) center. This is the format that BALLISTIX II will use to display the position of the center of the group. When you are done, BALLISTIX II displays a group summary to you containing the position of the center of the group and the group's size. You are then prompted as to whether you wish a detailed display. If you desire to see a shot by shot history of the group strike D. The detailed history shows you the position of each shot, the position of the center of the group and the size of the group, shot by shot. Also displayed is the variation and standard deviation of the group for you statistics nuts. Now that you have the detailed group history on screen, you can send this to your printer by striking P. Hitting any other key returns you to the Ballistics Table screen. 15 THE ZERO CHANGE CALCULATOR To enter the Zero Change calculator, strike Z when in the Ballistics Table. The Change Zero module of the program is designed with those of you who have access to a short range, but wish to zero your rifles at a distance not supported by your range facilities. This is much easier than trying to zero your rifle "3.65 inches high at 100 yards". The program lets you zero at 100 yards, then calculate the number of scope clicks you need to move to change the zero to another range. When the module is invoked, you will be shown the current zero range you have set, and you will be asked to enter the zero range you require, and the number of clicks required to change your scope 1 inch at 100 yards. When these have been entered, you will be told how many clicks up or down to adjust your scope, and what Minute-of-Angle the change will be. 16 MAXIMUM POINT-BLANK RANGE To enter the Point-blank Range calculator, strike B when in the Ballistics Table. The Point-blank range calculator module of the program is designed to allow you to calculate at what range you should zero your rifle to meet certain bullet path restrictions. Perhaps a short explanation of point-blank range is in order. Most people think that point-blank range means that your target is extremely close and that aiming is not required. This is almost true in one of those aspects. Point-blank means that range estimation and hold-over are not required in order to strike the target in a certain zone. Maximum point-blank range is the furthest range that you can shoot without correcting for distance. You just aim at your target and shoot. The bullet will strike within a specific zone. For big game shooters, that zone (in BALLISTIX II) is a 10 inch circle, roughly the "killing zone" of a deer. For varmint shooters, the zone has been shrunk to 5 inches. Let's take the case of the big game shooter. He has a 10 inch killing zone that he has to hit. This means that the bullet cannot climb above 5 inches above the target or drop to more than 5 inches below the target in order to hit the 10 inch zone. Therefore the point-blank range will be the farthest range that he could shoot not letting the bullet climb above or drop below the killing zone. BALLISTIX II calculates the maximum point-blank range of the load that you are using, and returns several parameters to you. What it tells you in the calculations are: ZERO RANGE - The range to zero your rifle at to achieve maximum point-blank range. MAXIMUM BULLET PATH ABOVE LINE OF SIGHT - This should be 5 inches for Big Game or 2.5 inches for Varmint. RANGE AT HIGHEST POINT - The range at which maximum bullet path is reached. BULLET PATH AT 100 YARDS - This can be used to check your zero on a 100 yard range. MAXIMUM POINT-BLANK RANGE - The actual maximum distance you can shoot that rifle/load without holding over to hit the killing zone. 17 The calculations needed to determine these variables are long and tedious (even for a computer). If you are running anything less than a 386 with a math co-processor, don't hold your breath. The program WILL eventually deliver the goods, but it will take time. (On a 486/33 the calculations take less than a second). What the program does in the calculations is to start with an arbitrary zero range close in. As the maximum height of the bullet path is pre-ordained by your choice of Big game or Varmint, BALLISTIX II runs an algorithm to determine bullet path out until the path at any point downrange is less than the previous path. This means that the bullet has reached it's maximum point. If that maximum is less than the pre-ordained 5 or 2.5 inches, BALLISTIX II increments the zero range and tries again. Once the program finds a bullet path that is equal to 5 (or 2.5) then the incrementing stops and the program runs the algorithm from the now known zero range to a point where the bullet path is -5 (or -2.5) inches. This delivers the required information. As you can see, the computer is working hard so that you will not have to. 18 THE CHARGE CALCULATOR To use the 'Powley' Charge Calculator, strike H when in the Ballistics Table screen. Many re-loaders are faced with finding a starting point with a new or non-standard (wildcat) load in the way of powder. If you can't find any information in the reloading manuals that you have handy on the load you wish to work with, you can use this module to get a starting load of IMR (Dupont) powders. The loads that this module calculates are not maximum or even near maximum, but remember, to be safe, ALWAYS START 10% LOW AND WORK UP. Watch for pressure signs at all times, and NEVER SWITCH POWDERS. As mentioned previously, this gives starting loads for IMR powders only. Even though another manufacturer may give one of their powders the same number as an IMR powder, THEY AREN'T THE SAME. Be smart, be safe. HAVING SAID THAT, MILE 300 COMPUTER SERVICES, HAVING NO CONTROL OVER THE USE OF THE INFORMATION PROVIDED IN THIS MANUAL OR THE PROGRAM ITSELF, CANNOT AND DO NOT ACCEPT LIABILITY, EITHER EXPRESSED OR IMPLIED, FOR RESULTS OF DAMAGE, OR FOR ANY LOSS OF LIFE, LIMB, PROPERTY OR PROFIT ARISING FROM, OR ALLEGED TO HAVE ARISEN FROM THE USE OF THE INFORMATION CONTAINED IN THIS MANUAL OR THE PROGRAM. When you enter the Charge Calculator, you are shown a menu which gives one of several choices: P PRINT FORMS - As there are many variables that must be entered in this module, there is a form which can be printed where you can write the information. This choice allows you to print multiple forms out for future use. I INPUT INFORMATION - Skip printing out a form, enter directly into the information input screen. O ONE FORM THEN INPUT - Print out one form, then go to the input screen to calculate a charge. X EXIT THE CHARGE MODULE 19 The information that you will need to aquire in order to use the Charge Calculator module is listed following: WEIGHT OF EMPTY CASE The weight of a fired case (with primer left in). WEIGHT OF WATER FILLED CASE The weight of the same case filled to the top of the neck with water. This gives an indication of case capacity. BULLET LENGTH The length of the bullet in inches from the base to the tip. BULLET DIAMETER The diameter of the bullet, in inches. BULLET WEIGHT The bullet weight in grains LENGTH OF EMPTY CASE The length of the case in inches. LENGTH OF CARTRIDGE OVERALL The overall length of a loaded cartridge, in inches. BARREL LENGTH The length of the barrel in inches. HEIGHT OF BOAT-TAIL The distance from the base of the bullet to where the boat-tail of the bullet joins the wide part of the bullet. DIAMETER OF BOAT-TAIL The diameter of the narrowest part of the boat-tail at the base. These final two values are needed in order to calculate more accurately the actual case capacity when a bullet is loaded. BALLISTIX II, when all of these variable are entered calculates a charge of Dupont IMR powder that you can use to start working up a load and displays this at the bottom of the screen. Should you wish any further information, strike D in order to get detailed information on the calculated load. This information includes expected muzzle velocity and a calculation of chamber pressure in copper units (c.u.p.). 20 THE BALLISTIC COEFFICIENT CALCULATOR To enter the Ballistic Coefficient Calculator, strike C when in the Ballistic Table. The ballistic coefficient of a projectile is a mathematical description of the drag of the projectile as compared to a "standard bullet". The ballistic coefficients of rifle bullets generally run in the range of .150 for flat nose bullets, to the upper .600-.700 range for pointed boat-tail bullets. The higher the ballistic coefficient, the less velocity that a bullet looses over the range of it's flight. Most of the time, you can obtain the ballistic coefficient of your bullets from a reloading manual published by the manufacturer of the bullet, but if you don't have a reloading manual, the Ballistic Coefficient calculator module of BALLISTIX II can help. The first thing that you should know is what type of bullet you are using. BALLISTIX II, on entry of the BC Calculator module gives you a choice of several bullets. As a matter of fact, all you need to enter is the bullet choice. The program gets the remainder of the information required from previous modules. Just strike the number of your choice for bullet type, and the program will do the rest. Once you have chosen, you are asked if you wish to have the calculated ballistic coefficient returned to the program for use in the Ballistics Tables and other modules. Strike 'Y' to accept the calculated BC or any other key to ignore it. 21 THE GRAPH SCREEN To display a graph of the path, drop and wind-drift; strike G when in the Ballistics Table. This module displays a small graph showing the bullet path versus the bullet drop, and the wind drift across the line of sight. Other information shown is the zero range, and the distance that the bullet crosses 5 inches below the line of sight (see Maximum point-blank range); THE TARGET LEAD CALCULATOR To use the Target Lead Calculator, strike A when in the Ballistics Table screen. It is always useful to know just how much you have to lead a moving target when that trophy buck is running across your line of sight at 250 yards (not that I advocate shooting at a running buck at long distances). The lead calculator module is included to give you some indication of how far out in front of your target you have to hold in order to hit it as it goes by. Given are some representative speeds of animals at the walk, trot and run. These aren't carved in stone, but from what I have seen and read, they are in the ball park. All you have to do to use the screen is enter a target speed in miles per hour, BALLISTIX II does the rest and gives you lead distances from 0 to 500 yards. 22 COMPARING TWO LOADS To compare two loads, strike M when in the Ballistics Table. At times it is nice to be able to compare the ballistics of two seperate loads. BALLISTIX II gives you the oportunity to do this in the Compare module. When you have entered the module, the first screen that you see is the same Environment Variable entry screen that you were presented with when you first started BALLISTIX II. Only the title of the screen is different. The default variables are the same as the variables of the main load you were working with. Unless you wish to compare loads with different environmental variables, just hit to accept the shown values, or use the arrow keys to move to a variable and enter a new value. When you are done, hit . The second screen shown is the Load Variables entry screen, again as when you started the program. Modify these to reflect the load you wish to compare to the main load. Change the values as described above, when you are done, hit to display the compare screen. The compare load screen shows you the two loads side-by- side, in seperate colours. The Velocity, Energy, Drop and Path are displayed. This allows you to compare the performance of the two loads. At the bottom of the screen are the calculated ballistic coefficients of the two loads. 23 SHELLING OUT TO DOS At times it is nice to be able to make a system call. To shell out to COMMAND.COM, when in the Ballistics Table, strike S. THE RIFLE DATABASE To enter or view information in the Rifle database attached to your current load, strike I when in the Ballistics Table. BALLISTIX II gives you the opportunity to attach certain rifle and scope information to the load you are working with. To do this, strike I when in the Ballistics Table screen. If there is any rifle information attached to the load you are working with, it will be displayed on screen, if there is not, you are asked if you would like to enter any information. To do this, answer 'Y'. The information that can be entered is general information about the rifle you are using. Manufacturer, model, serial number, barrel length, scope make, model and serial number and a sequence of 5 comment lines where you can enter any special information such as custom features, etc. The information in the file could be invaluable at a future date for insurance purposes, etc. It also is nice to be able to call up pertinent features of the rifle which is shooting the current load. The information is kept in a special file called RIFLE.DBR which is created when needed, and stored in the working directory where you keep the program. QUITTING BALLISTIX II To quit BALLISTIX II, strike either or Q when in the Ballistics Table screen. When you quit BALLISTIX II, all of the files that may have been opened are closed. The current load information is stored in a filed called START.UP which is used to initialize the program when next it is started. Then you are returned to the DOS prompt in the working directory.