ABOUT BULLET FLIGHT 1.20 BULLET FLIGHT (BF120.EXE) is the sole property of Donald B. Arp, and is not to be copied or reproduced. The Trial Version (TRYBF120.EXE) and ONLY that Version may be copied, along with the supporting files which must accompany it: RCOEFS.TXT, BFINFO.TXT, README.1ST, and PRINTDOC.BAT. I have made a thorough effort to "debug" this program and to make sure that the information produced by it is reliable. However, since I am only human and could possibly have missed something, please pay careful attention to the following DISCLAIMER: This program is provided 'AS IS' and I specifically disclaim all warranties, expressed or implied, including but not limited to implied warranties or merchantability and fitness for a particular purpose. In no event shall Donald B. Arp be liable for any loss of profit or any other damage which result from the use of this program, including but not limited to special, incidental, consequential or other damages. Donald B. Arp, Author And now that the formalities are out of the way, let's take a look at BULLET FLIGHT 1.20. My goal in writing this program was to produce a program which would produce ABSOLUTELY PRECISE results in its final calculations. To accomplish this, BULLET FLIGHT uses a numerical integration technique in its calculations. Results are calculated at EACH YARD out to the maximum range you specify. Naturally, this takes more time than some other methods. But, if precision is the utmost consideration, then the few seconds delay should be worth the wait. On the 80286 (no math co-processor), AT-compatible computer on which this program was written, a full set of calculations out to a maximum range of 1000 yards took about six seconds. My second priority was to write a program which would produce PRACTICAL information for the shooter. Consequently, BULLET FLIGHT is not full of "bells and whistles". No graphing functions is provided. Why? Because trajectory graphs all look pretty much the same. (The only things that change much are the figures on the X and Y axis of the graph.) And I wanted a program which would run on anybody's computer, regardless of the graphics interface they are using. No accomodation is made for saving the results to a file. Why? Because it is just as easy to recalculate a set of data as it is to reload it from disk. Besides, that keeps the program simpler. And the less the program has to access your drive, the less chance there is for something messing up. So what DOES a shooter need to know? He needs to know where his bullet will be at any practical range, how much "knock-down- power" it has left, how much to adjust his scope to rezero for extreme ranges (unless he is a pretty good judge of "holdover"), how the wind will affect his bullet, where to zero at close range to get on-paper at long range, and maximum bullet rise above line-of-sight. Other considerations only come into play when you compare one cartridge to another. Things like recoil, time of flight, and downrange velocities are useful here. I make no apologies for limiting the maximum range of BULLET FLIGHT to 1000 yards. The only reason that I set it THAT far is because there are 1000-yard competitive shooting events. As for myself personally, I consider 400 yards to be the PRACTICAL limit for shooting. And that is true ONLY if you can get "sandbag" steady. This program was written to produce a black-and-white screen display without any graphics. This was done intentionally to insure that it would run on any IBM-compatible computer, regardless of monitor type or graphics interface. The only requirement is that your monitor run in 80-column mode. This program uses the G1-Drag Function to calculate velocity losses which result from air drag on a bullet. A lot of calculating has to be done for the program to figure all the variables it calculates. The greater the maximum range you specify, the greater will be the time necessary for the program to perform its calculations. This time interval will depend on the speed of your particular computer. The figures calculated by this program are, for all practical purposes, identical to the figures contained in the Speer Ballistics Tables (which are also based on the G1-Drag Function). However, with this program, you are not limited to a certain zero-range, nor are you limited to a 500-yard maximum range (1000 yards is the limit). In addition to remaining velocities and trajectory points, this program also calculates kinetic energy (ft/lbs), scope adjustment to obtain new zero, the bullet's time of flight, bullet drift in a crosswind, close-range zero range, maximum bullet rise above line-of-sight, free recoil, and optimum zero ranges (explained below). It will also standardize ballistic coefficients to conditions other than sea level. Also, the program will produce a printout for any interval you choose, even down to EVERY YARD in the range. There are some pieces of information which you will have to look up, probably in a reloading manual of your choice. These are: the ballistic coefficient of the particular bullet you are using, the muzzle velocity of that bullet, and (if you want recoil information), the weight of the powder charge for the cartridge. The Trial Version of this program is intentionally limited. It only allows a Maximum Range of 200 yards, prints results at 50-yard intervals only, does not calculate close-range zero range, maximum bullet rise or recoil, does not provide for hardcopy printout, and does not allow you to standardize the ballistic coefficient to conditions other than sea level. If you want to obtain a Registered version of this program, send your name and address with a registration fee of $15.00 to: Don Arp, 1214 Irwin Avenue, Maryville, Tennessee 37804 If you should find an error in the results which BULLET FLIGHT produces or if the program should malfunction somehow, please feel free to let me know. If you have any suggestions which would make this program more beneficial to you, let me know that too. I won't guarantee that I will USE every suggestion I get, but you can rest assured that I will CONSIDER every suggestion you send me. ***** WARNING...WARNING...WARNING ***** --------------------------- The Registered Version contains your name and address on the opening screen. DO NOT ATTEMPT TO ALTER OR REMOVE THIS SCREEN. The program MUST have this data INTACT to run. Moreover, the program will SELF- DESTRUCT if this data is not intact. Also, do NOT write-protect your disk. If you do, the program will not run. To start the Registered Version, type BF120 at the DOS prompt. To start the Trial Version, type TRYBF120 . When the program starts, you will be asked to enter several pieces of information. Although most of this information is not printed out on-screen (in order to conserve screen space), it is printed as a header when you ask for a printout to your printer. 1. HEIGHT OF SIGHTS. This is the distance (in inches) of the centerline of the gun's sights above the centerline of the gun's bore. Most "open" sights are located about .75 inches C-C above the bore. Scopes (due to the particular mounting hardware) are usually located at 1 to 2 inches C-C above the bore. Note: This is the distance from CENTERLINE TO CENTERLINE of sights to bore. 2. BULLET WEIGHT. This is the weight of the bullet in GRAINS. 3. BALLISTIC COEFFICIENT. This is a DECIMAL NUMBER which represents the air drag capability of a bullet. You can look this up in any of the reloading manuals available for the particular bullet you are using. Values of .01 to 1.0 are acceptable to the program. 4. MUZZLE VELOCITY. This is the speed in feet-per-second at which the bullet leaves the barrel. This information is available in reloading manuals. The minimum allowed is 250 ft/sec, maximum is 4365 ft/sec. 5. MAXIMUM RANGE. Here you tell the program what maximum range (in YARDS) you want it to calculate to. For instance, if you want trajectory information out to 500 yards, enter 500. The Registered Version of the program will calculate to a maximum of 1000 yards, but the Trial Version only allows a maximum of 200 yards. 6. ZERO RANGE. This is the range (in YARDS) at which you want to zero your gun. You cannot exceed the Maximum Range selected above. 7. YARDAGE INCREMENT. This tells the program which ranges (in YARDS) that you want it to print information for, out to the maximum range you have selected. For instance, if you want to know what your bullet is doing every 25 yards, enter 25. The smallest increment you can choose is 1 yard. The largest is the maximum range you chose. 8. RECOIL INFORMATION. If you want to know how hard your gun "kicks", enter "Y" (for yes). You will then be asked to enter two other pieces of information.--The weight of the powder charge in GRAINS, and the weight of your gun in POUNDS. (Don't forget to add the weight of your scope & mounting hardware, sling, and ammunition in the magazine when you figure your gun's weight.) If you don't want this information, enter "N" (for no). 9. STANDARDIZE COEFFICIENT. Ballistic coefficients as listed in the reloading manuals are almost universally calculated at sea-level conditions. However, you may want to find out what your bullet will do at conditions other than sea level. Altitude, temperature, and barometric pressure all affect the density of the air. And the denser the air, the greater will be the resistance to the bullet passing through it. If you choose to standardize the coefficient, you will be prompted to input the conditions you want. The Standard temperature and barometric pressure for the altitude you select are printed in parenthesis. You can use them or put in whatever value you prefer. If the value you want is above the cursor, just press ENTER. You can select any altitude from 0 to 15000 feet (even feet only), temperatures from -100 `F to 150 `F, and barometric pressures from 15.00 to 35.00 In/HG (inches of mercury). 10. CROSSWIND SPEED (MPH). This is the crosswind velocity which you want the program to use in calculating bullet drift. Any value from zero to 50 is acceptable. 11. VERIFY. The last question asks you to verify all the data which you have entered with the question "Is all data correct? Y/N". If you want to change something, enter "N" (for no). If all the data is correct enter "Y" (for yes) or simply press ENTER. Also, read "RE-ENTERING DATA" below. On any piece of information, if you should enter a value which is out-of-range or invalid, the program will reject your input and require you to re-enter that piece of information. --------------------------------------------------------------------- The program will take the information you have entered, and will proceed to calculate several items for you. (A great deal of calculating has to be done, so this takes a few seconds.) The printout includes the following: 1. RANGE. Distance in yards at each yardage increment you selected. 2. SPEED. Bullet velocity in feet-per-second at each range. 3. TRAJ. Abbreviation for "TRAJectory". Most people think of this as "drop". This is the location of the bullet above or below the line-of-sight at each range. A positive number means that the bullet is ABOVE the line-of-sight. A negative number means that the bullet is BELOW the line-of-sight. 4. ADJ. If you are using a scope, this is the amount of ADJustment (in INCHES, not clicks) that you would need to dial in to adjust your zero to the range in the RANGE column. A positive number means that you would need to move your scope adjustment UP. A negative number means that you would need to move your scope adjustment DOWN. For instance, if your gun is zeroed at 100 yards and you want to re-zero to 200 yards, look up the ADJ value listed in the 200-yard data line. Then move your scope up/down adjustment the number of inches you found in the 200-yard ADJ line. Remember this is INCHES, NOT CLICKS. 5. FT/LBS. Most people think of this as "knock-down-power". This is the kinetic energy of the bullet, in foot/pounds, at each range. 6. TIME. This is the bullet's time-of-flight (seconds) at each range. Why include this in the chart? This is the absolutely reliable way to determine which bullet shoots the flattest. The quicker the bullet gets there, the flatter its trajectory. When comparing two bullets, the one which crosses the finish-line first is the flattest- shooting of the two. It is surprising how much difference just a few hundredths of a second will make in the drop of a bullet at 500 yards. 7. DRIFT. This is the number of INCHES your bullet will drift to the left or right at the crosswind velocity you selected. This crosswind is considered to be at a right angle to your line-of-fire. In addition, the program will calculate a CLOSE-RANGE ZERO for you. This is the close-up range at which to zero your gun in order to get "on-the-paper" at the longer zero range you specified. However, if you specify a zero range which is relatively close to the muzzle, the Close-Zero Range and Zero Range will be the same. Also, the program calculates the maximum bullet rise (in inches) above the line-of-sight, and tells you at what range this maximum rise occurs. If the bullet is still rising when it reaches the maximum range you selected, the printout on-screen will tell you. Once the program has calculated the trajectory information for you, you can get an OPTIMUM ZERO RANGE. To use this feature, you simply enter the maximum height (in inches) above line-of-sight that you want, and the program will tell you at what range to zero your gun to get it. (If the height you choose would result in a zero beyond the Maximum Range specified, the program will give you an error message.) For instance, if you want to zero your gun so that the bullet will never be more than 2 inches higher than your line-of-sight, simply enter 2 when the program prompts you to enter Maximum Rise. Then, by pressing "R", you can have the program to re-figure the trajectory chart based on this new zero range. To save a multitude of recalculation and quite a bit of time, this Optimum Zero feature uses a shortcut method to figure the zero range. Although this method is not as accurate as a full-blown analysis, it is accurate to within a few yards, and is certainly more than accurate enough for all practical purposes. And it saves a BUNCH of time. Also, you can select a NEW ZERO RANGE. Only the portion of the calculations which pertains to trajectory will be recalculated, which requires about 1/3 the time of a full set of calculations. GETTING A PRINTOUT ------------------ If you want to print the information to your printer, you will be prompted to enter two other pieces of information. These are used in a header for the hardcopy printout. 1. DESCRIPTION OF GUN. Here you enter whatever description you want of the particular gun you are calculating information for. For instance, 30-06, 7mm Magnum, .243 Winchester, etc. This can be worded however you want it, up to 35 characters in length. 2. DESCRIPTION OF BULLET. This is a description of the bullet you are using, worded however you want it, up to 35 characters in length. When printing is finished, the chart will be re-displayed on-screen. RE-ENTERING DATA ---------------- The program stores all information which you enter. Therefore, if you want to go back and change some portion of the information you originally entered, it is not necessary to re-enter the whole thing again. The information which you have previously entered will be printed at each prompt. For each entry which you DO NOT want to change, simply press ENTER. The program will use the value which you entered before. For instance, if you only want to change the Muzzle Velocity, the only new figure you will have to enter will be the new Muzzle Velocity--just press ENTER on all other prompts.