I was sitting on a high spot calling into the willows when a coyote stepped out of nowhere into my view. In order to see over the high sagebrush I was calling in, I was situated a hundred feet above the valley floor.
Responding coyotes will sometimes come close and sometimes hang up. Either way, they will be at a downhill angle to me. And the closer they come, the steeper the angle will be. With the kill area of the coyote as small as it is, some calculation of the angle shot will be needed to get them on the stretcher.
One of the things I really like about hunting/calling coyotes is the level of precision required for taking longer shots. Although I love the rush of a coyote coming into the call, the precision necessary to consistently put fur on the stretcher when the coyote is hung up out there a ways is just as much fun.
Coyotes require a more precise aim than you might think from first appearances. However, anyone who has peeled all the hair off of a coyote knows the vitals take up a small area. Many coyotes have had their hair parted and have escaped without a scratch. A couple of inches of miscalculation will result in a miss and a much smarter coyote every time.
Even slight angles can impact the travel of the bullet, but steeper inclines can easily cause a miss or wounded song dog at shots as close as 100 yards. At longer ranges, the problem is even more pronounced. Rememer, a coyote is not a paper target that is always perfectly broadside.
The rule to remember is that the bullet will always impact higher — whether shooting uphill or downhill. This should be compensated for to achieve superior accuracy. The reason is the time and distance that gravity affects the bullet is less than the inclined line of sight would have you believe.
It goes back to simple geometry that we have all long forgotten. All shots that we take that are at an inclination, up or down, can be drawn as a triangle — specifically a right triangle. The side of the triangle that is opposite the 90-degree angle is the hypotenuse and represents the line of sight (LOS). The horizontal side represents the actual yardage (true ballistic range) that gravity affects the bullet (See Diagram on Page 29). Therefore, the TBR is shorter than the LOS and the bullet will impact higher because gravity does not have as much time to affect its trajectory. The question is how much compensation for each angle of inclination.
When shooting an elk in the couple hundred yard range, experienced hunters know a slightly lower aiming point should take care of the compensation because the kill area on an elk is fairly large. I have hunted with folks that just adjust their point of aim (POA) through experience and estimation with surprising accuracy. The problem is they have missed many coyotes to gain that experience. Trying to hit that hung up coyote down a 25-degree hill at 200 yards can result in a miss if the correct hold is an approximate guess. But with a little math and technology, those coyotes can make fur while we are learning.
When I first set up in my stand, while I am waiting for the area to calm down a bit from injecting myself into the geography, I will range out some of the landmarks that are near the lanes of approach I think a coyote will come from. The longer range ones are especially important, because as the minute of angle (MOA) increases with range, so do mistakes.
While I am doing this I also estimate the angles up or down for the shots. From experience of shooting in uneven terrain in controlled practice conditions, I know when the angle is enough to affect the bullet for a miss at that range. Like estimating range, estimating angle becomes easier the more you do it. At most reasonable coyote distances — 200 yards or less — just knowing if the angle is over or under 30 degrees will give the shooter an idea if they should estimate a lower aiming point for a shot in the boiler room.
I realize most hunters are not going to do the math in the stand like a precision rifleman or competition shooter, but knowing how the math is done will give coyote hunters an idea how much to account for.
Before I start compiling data on how the rifle shoots at angles, it is important to know how it shoots on level ground. All computations will be made in relation to the level ground trajectory. I generally sight my coyote gun in at 100 yards. For hunting, I like scopes that have a reticle that is adequately graduated to quickly compensate for bullet drop at various ranges.
Reticles like ART (Advanced Reticle Technology), Shepherd Scopes and Leupold, to mention a few, that have drop compensation marks right in the glass, make distant shots simple after the yardage is known. After the inclination is figured in and a true ballistic range (TBR) calculated, the proper hold over is found in the scope and BAM. These reticles often start with 100 yard zero.
I start out by working up the most accurate load for the rifle I am using and create a ballistic chart for that rifle and load. Now I know where the bullet strikes at all the distances I will encounter on a level field. After I know what it will do on level ground, I can adjust for angle easily in the field using one of several methods. The simplest is to calculate the actual yardage that affects the bullet (TBR) and use that number to decide which drop compensation line to use on the reticule.
The first thing that needs to be calculated is the angle of incline. There are several ways to estimate the angle. Precision tools are available to do this, but again, most of us can estimate over or under 30 degrees and over and under 45. After I figure the angle on the stand, I write it down for later use. This angle can be converted to the cosine using a chart. The chart below is a conversion for some angles. It would suffice for most hunting conditions, but a calculator or one of the charts available on the Web can give a precise estimation for all angles. The cosine of the angle is the decimal equivalent of it and this is the number that is multiplied by the yardage of LOS.
SLOPE ANGLE MULTIPLY BY UP or DOWN RANGE
05 Degrees — .99
10 — .98
20 — .94
30 — .87
40 — .77
50 — .64
60 — .50
70 — .34
80 — .17
90 — .00
I keep a data book on my calling guns and I also have notes on stands and conditions of each. I also shoot my calling gun regularly and keep notes on performance and impact in the different temperatures I shoot. Some of this is more necessary for competition shooting, but temperature affects bullets much more than you think. At distances of a mere 100 yards, a 30-degree drop in temperature can cause the bullet to impact low as much as 5 or 6 inches. So a coyote shot at 100 yards in 35-degree weather would be a miss at 5 degrees if the same POA is held.
I call good stands regularly and the angles never change. When I am scouting out good stands, I write down yardages and angles and have it all figured before I set up. I keep quick reference trajectory notes in the flip up cap of my scope cover. I also figure the wind and how the sun will affect the stand and if it will be a better morning or evening stand and keep it in my notebook.
Another method of configuring inclination into the data book is to use ballistic programs like the one from Holland Shooting Supply. By using his ballistic program to figure trajectory of your most accurate load, the computer will also help figure in angles of inclination to come up with the correct true ballistic range (TBR). The program will print out a ballistics card that can be laminated and taped to the stock of the rifle or kept in the data book. This data can be coupled with ART (Advanced Reticle Technology) for a system that is incredibly precise for long-range hunting of coyotes in uneven terrain. The nice thing about this system is the math is done on the computer and the card gives the shooter an idea of correction for an angled shot and he can compensate for it with the reticle.
There is a neat little tool called an angle cosine indicator that attaches to the rifle and will immediately give the angle the rifle is held at and the correct cosine. It saves the step of looking up the cosine as it is displayed in the decimal. It will give the correct cosine right from the angle the rifle is resting at. It is a very precise way to get the correct cosine to multiply out.
I remember using a slide rule in college because the new-fangled calculators that were coming out cost as much a several of the expensive books I needed. The only college assistance fund available in those days was a graveyard shift at the 7-11.
Now, a really good calculator costs very little and everybody has several around the house. The same can be said for laser rangefinders — except for the part that they cost very little. Still, there are models within the grasp of most callers that can afford a rifle. I have come to depend on them for calculating range and they prove to me that I am not as good as I think I am for estimating distance.
The best way to figure out these inclination problems in a hunting scenario is to use a laser rangefinder that figures in the inclination. It is the new popular option available in rangefinder technology, and a very useful one. These devices are about the size of a small camera and fit in a jacket pocket or in a belt loop case. They calculate the line of sight and true ballistic range and also the angle of the shot. Knowing the rifles trajectory at various yardages allows the shooter to use the correct hold for the true ballistic range and take the shot. I make all these calculations when the area is settling before I start squealing.
Is all this necessary with the flat shooting rifles we hunt with today? Well let’s just see. Let’s say I have a coyote hung up at 300 yards (LOS) and it is a downward angle of 30 degrees. The cosine of 30 degrees is .87. 300 x .87=261 yards (TBR). Are those 39 yards going to make a difference? According to my charts, a 52 grain .22 bullet traveling at 3,000 fps and sighted in at 100 yards at 57 degrees Fahrenheit with no wind will drop 14.8 inches at 300 yards. The 40 yards could make a couple inches difference, and with a 5-inch center punch on a coyote, incorrect calculation of angle could result in a wounded critter or a miss.
I usually get the coyote in a little closer when calling and angle doesn’t play as important a role the closer the target is or the smaller the angle, but it is good practice to be aware of.
Plus, with the number of folks taking to the calling woods these days, long shots are becoming more common. I often find coyotes hunting out in pastures and hayfields. These situations usually end up in a long shot. When that coyote is hung up out there, knowledge of precise shooting and figuring in the angle of inclination will definitely increase your chance of a precise hit.
Dave Morelli, of Idaho, is a field editor for T&PC.