Introduction
1. Desmond T. Burke, Canadian Bisley Shooting, 1970, pp. 133–134.
2. G. David Tubb, Highpower Rifle, 1993.
3. “Minutes” refers to the sight setting in minutes of angle. A minute of angle (MOA) is a fraction of a circle (1/21,600). For shooting purposes, it is commonly thought of as being equivalent to 1 inch at 100 yards. That is, a sight change of 1 minute will move your group 1 inch at 100 yards. Because minutes refer to angles, the farther you are from your target, the greater the movement; that is, a sight change of 1 minute will move your group 5 inches at 500 yards and 10 inches at 1,000 yards. Most sights are calibrated in minutes, with smaller increments in ¼ minutes. Some shooters refer to the smaller increments on their sights as “clicks” (because the mechanism gives a small “click” as the sight is adjusted) whether they are ¼ minutes or some other measure.
Chapter 1
1. Bill McRae, Outwitting the Wind (publication unknown).
2. External ballistics is the science of the bullet in flight.
3. A fairly average kind of handload has the 155-grain bullet traveling at 2,900 fps (muzzle velocity). This roughly translates to a speed of 1,977 mph. All shooters strive to ensure that their bullet speed does not drop below the speed of sound before it passes through the target; the speed of sound is roughly 818 mph. The average of these is about 1,397 mph.
4. Thanks to Clint Dahlstom for pointing this out and Jim Bullock for confirming it.
5. FBI Academy Firearms Training Unit, Advanced Rifle Training; see www.firearmstactical.com/pdf/fbi_observer_sniper_manual.pdf.
6. Norm Barber, a well-known Canadian F-Class shooter and a meteorologist by trade, explains it this way: The reason humid air is less dense than dry air is due to the atomic weights of the molecules making up dry or humid air. Dry air is around 75 percent N2 (atomic weight 28) and 25 percent O2 (atomic weight 32). In humid air, some of the 28- and 32-weight molecules are displaced by H2O molecules (atomic weight 18). Thus the more H2O in the air, the more 18-weight molecules are displacing the heavier 28- and 32-weight molecules and the given volume is less dense, or lighter.
7. Charles F. Young, “Wind Reading—Another Way of Looking at It?” Tactical Shooter (April, 1998).
8. Our friend Wordsworth Price advises that, in purely scientific terms, “velocity” has both magnitude and direction, while “speed” is the correct term to refer to magnitude only. Therefore, strictly speaking, one should not talk about velocity and direction, but rather speed and direction. However, as Wordy observed, it is likely that everyone knows what we mean.
9. Desmond T. Burke, Canadian Bisley Shooting: An Art and a Science, 1970, p. 123.
10. In fact, at most ranges, the flags are considerably above the line of flight of the bullet. As Clint Dahlstrom stated in his notes to us following the publication of the first edition of The Wind Book: “Flags are almost always a lot higher than the culminating level of bullet path, which is about 10 feet. The ‘standard’ 1,000-yard flag is 15 feet long and 6 feet wide at the halyard, which means that with zero wind, the flag hangs 18 feet from top of pole to the tip of the flag (15 feet plus half of the 6-foot width). The usual clearance of the flag tip above the ground is about 6 feet or so, which indicates that the middle of the flag is about 21 feet above the ground.”
11. E.G.B. Reynolds and Robin Fulton, Target Rifle Shooting, 1972.
12. Burke, Canadian Bisley Shooting, p. 123
13. As we will discuss later, wind from the left moves the bullet to the right and requires left windage to correct; in short, left wind requires left windage on the sight.
14. A headwind increases bullet drag (air resistance), and this affects the velocity and the trajectory, resulting in a slight difference in vertical displacement (completely negligible at less than 600 yards, and only about two-thirds of a minute of angle at 1,000 yards). Since wind rarely shifts from a pure headwind to a pure crosswind during a shoot, this effect is usually not an issue; the shooter usually builds the vertical deflection into his elevation requirement on the day.
15. Whereas decimal targets are typically scored X, 10, 9, 8, 7, etc., Bisley-style targets are typically scored V (V-bull), 5 (bull’s-eye), 4 (inner), 3 (magpie), 2 (outer), although there are some local variations.
16. Mirage can also be seen in cold climates, just not as reliably. It can often appear over snow on a bright winter’s day, but it can be flighty and hard to read. The appearance of mirage depends on layers of air at various temperatures, and moisture in the air makes the mirage more visible.
17. In doing research for this book, we have found that there is definitely room for controversy here. Surveyors using optical methods assure us that they will work at night to minimize the effect of heat waves distorting their readings. Benchrest shooters swear they can see that the image of the target has moved with their well-mounted rifles and powerful scopes. For practical purposes, any change in elevation would be consumed in the day’s sight setting, except for the circumstance where the intermittent clouds produce intermittent mirage. Under this circumstance, the shooter may well need to make elevation adjustments to accommodate the mirage.
18. Young, “Wind Reading—Another Way of Looking at It?”
19. More efficient calibers will usually fly flatter and faster, but the principles of understanding their time in flight are the same.
20. For the reader who is interested in the mathematical formulas, the clearest and most thorough explanation that we have found is in Burke’s Canadian Bisley Shooting.
21. While 700 yards in not shown on this chart, the deflection is approximately 11¾ minutes of angle for a wind at 20 mph.
22. Burke, Canadian Bisley Shooting, p. 117.
23. While the bullet is moving more slowly for the second half of its flight, under most circumstances this decrease in velocity has only a slight effect on deflection. To prove this to yourself, run your ballistics software with bullets traveling different velocities. In practical terms, there are factors far greater in wind reading than the small differences caused by decelerating bullets.
24. As you will read in the “What Others Say” section following, the difference required is extreme.
25. One of the students in our Wind-Reading Course was MWO David Atkins, a member of an artillery unit in the Canadian Forces. He commented that it was very clear that a near-muzzle ricochet would have far greater deflection than a near-target deflection. The same goes for wind deflection.
26. Burke, Canadian Bisley Shooting, p. 131.
27. For diagrams of these three examples, see John Simpson’s “Words of Wisdom” in chapter 5.
28. To make correct adjustments you must also know your sight. Target rifle sights are usually in genuine minutes and quarter minutes, although they come in British/US or Australian minutes (which are different-sized measures). Telescopic sights are often built with either quarter-minute or third-minute clicks, and then scaled with four clicks to the “minute,” so that the size of the minute can be coarser or finer. Smallbore sights are usually adjusted in terms of “clicks” and rotations, and at least one expert in smallbore shooting says that top smallbore shooters lose more points by not knowing their sights than in not judging the wind correctly.
29. The Plot-o-Matic (EZ-Graf) is an ingenious device used to assist the shooter in keeping the group centered and interpreting wind conditions. It is further described and discussed in chapter 3 in the section on recording methods and tools.
Chapter 2
1. George Stidworthy, “Reading the Wind,” Rifle magazine (March/April 1981).
2. For more information about developing a game plan, see chapter 3, “Techniques and Tactics.”
3. For details on using flags, bookends, and primary and secondary conditions, see chapter 3, “Techniques and Tactics.”
4. G. David Tubb, Highpower Rifle, 1993.
5. Charles F. Young, “Wind Reading—Another Way of Looking at It?” Tactical Shooter (April, 1998).
6. Ibid.
7. The Plot-o-Matic (EZ-Graf) is an ingenious plotting device described in chapter 3.
8. Young, “Wind Reading—Another Way of Looking at It?”.
9. Burke, Canadian Bisley Shooting, p. 133.
10. Ibid, p. 131.
11. E.G.B. Reynolds and Robin Fulton, Target Rifle Shooting, 1972.
12. Young, “Wind Reading—Another Way of Looking at It?”.
13. Burke, Canadian Bisley Shooting, p. 128.
Chapter 3
1. Linda K. Miller, “Snatch the Pebble,” Precision Shooting (July 2000), and Favorite Stories on Winning, 2003.
2. Desmond T. Burke, Canadian Bisley Shooting, 1970, p. 123.
3. We have observed elite shooters in hard wind conditions use their “angle flag” as the primary indicator. They find their mean sight setting for that angle, and then they tune their actual sight setting with an assessment of the wind velocity.
4. Burke, Canadian Bisley Shooting, p. 123.
5. The basic math is in Canadian Bisley Shooting, and considerable details are shown in two Tactical Shooter articles: “Kentucky Windage Goes High-Tech” and “The Question Is Blowin’ in the Wind.”
6. Snowbound winter evenings are a typically Canadian thing! Readers from other countries need to substitute the local conditions that would keep them from being out at the range.
7. Burke, Canadian Bisley Shooting, p. 123.
8. These devices are commonly available in stores that cater to recreational sailors and yachtsmen. We have tried several and have found that the ones with the exposed wind vanes are a little too fragile, and we prefer the ones that have shrouded wind vanes.
9. The availability of ballistics software is improving rapidly. A recent Internet search yielded several promising packages, most of which offered a 30-day free trial.
10. The wind flag diagrams are built from data for 7.62 NATO-issue ammunition. The observant reader will notice that the windage chart in Figure 45 shows that the 155-grain Sierra bullet with a muzzle velocity of 3,100 fps requires considerably less windage correction.
11. Bill Richards made these remarks when he spoke to the Ontario Team to Bisley at the Millennium Matches in the year 2000. The Ontario Team graciously included us at this team function. Bill’s “words of wisdom” are also included in chapter 5 of this book.
12. George Chase’s words of wisdom are also included in this book.
13. George Chase showed us a neat trick. He draws a little pictogram of the wind flag (angle and/or velocity) that goes with each group right above the group, so he can quickly see what sight setting he needs.
14. The “theory of a group” establishes that when a series of shots are fired from a rifle at the same point of aim, they will seldom pass through the same hole. Instead they create a pattern on the target called a group. It also provides that the size of the group will increase in proportion to the range.
15. Target rifle shooters use .308 ammunition, iron sights, and a sling, all of which increase their group size, compared to F-Class shooters, who use any caliber, telescopic sights, and a bipod or front rest.
16. This is entirely different from (but would certainly add to the effect of) “Burke’s bulges,” which are group deformities caused by canting errors, as described in Canadian Bisley Shooting, pp. 96–109.
17. Miller, “Snatch the Pebble” Precision Shooting (July 2000) and Favorite Stories on Winning.
18. Burke, Canadian Bisley Shooting, p. 134.
19. “Recce” is a British term, short for reconnaissance.
20. Charles F. Young, “Wind Reading—Another Way of Looking at It?” Tactical Shooter, (April 1998).
21. Burke, Canadian Bisley Shooting, p. 131.
22. We have used this exercise in some of our courses, where we emphasize that because the reading you will get is dependent on the angle you read from, it is essential that you align your spotting scope with your line of fire.
23. That would be a 49 out of a 50 possible score, a fine long-range score in good conditions and an outstanding one on a blustery day! From Canadian Bisley Shooting, p. 125.
24. Burke, Canadian Bisley Shooting, p. 120.
25. Data taken from the Parker wind calculator.
26. These data are taken from commonly available plotting diagrams—notice small differences from the Parker chart information in the previous figure. If you run ballistics software for your own .308 load, you will find further small differences.
27. Burke, Canadian Bisley Shooting.
28. When we teach our wind-reading course, we use the team setup to separate the roles of firing the perfect shot (the shooter), centering the group (the plotter), and reading the wind (the wind coach). We do this so that each person can focus on one job at a time, and so build the skills required to do each job well. While acting as wind coach, the student can watch the wind all the time, including when the shot is being fired. Most students are surprised by how much the wind can change during those last few seconds.
29. Young, “Wind Reading—Another Way of Looking at It.”
30. Burke, Canadian Bisley Shooting, p. 133.
31. G. David Tubb, Highpower Rifle, 1993.
32. Burke, Canadian Bisley Shooting, p. 124
Chapter 4
1. Linda K. Miller and Keith A. Cunningham, “How Good Shooters Think,” Favorite Stories on Attitude, 2003.
2. Desmond T. Burke, Canadian Bisley Shooting, 1970.
3. E.G.B. Reynolds and Robin Fulton, Target Rifle Shooting, 1972.
4. Raymond Von Wahlde, “Kentucky Windage Goes High-Tech: Development of a Laser Crosswind Sensor,” Tactical Shooter (March 1999).
5. Charles F. Young, “Wind Reading—Another Way of Looking At It?” Tactical Shooter (April 1998).
6. Burke, Canadian Bisley Shooting, p. 125.
Chapter 5
1. One mile is 5,280 feet or 1760 yards or 1609 meters.
2. “Burke’s bulges” refers to the group that results from canting errors; Desmond T. Burke, Canadian Bisley Shooting, 1970, pp. 96–109.
3. This reminds us of the old Canadian saying: “If we are attacked by a bear in the bush, I don’t have to outrun the bear—I only have to outrun you!”
4. Added to the second edition of The Wind Book.
5. Added to the second edition of The Wind Book.
6. The Canadian Marksman is the journal of the Dominion of Canada Rifle Association.
7. The values are representative of issue ammunition, originally very likely IVI. Your own rifle/ammunition combination may well require slightly different base numbers. For example, the numbers yielded for 500 yards in these charts is almost exactly Linda’s .308 rifle/ammo requirement for 600 yards.