Angled shooting - It is a situation that leads to lost arrows and frustrated hunters all around the world. Whether you are chasing mule deer in Western hill country or trying to best your friends at the closest Total Archery Challenge course, you'll have to understand angle compensation. It also helps to correctly apply it in practice to remain as accurate as possible.
Angle compensation refers to the fact that gravity only affects an object on a linear plane - meaning it works over a horizontal distance and not a straight line from you to your target.
Let's say you are hunting from a treestand - this is a concept many of us in the East are familiar with. If you use your rangefinder on a deer to find that it is 38 yards away on a straight path from you, the actual horizontal distance between the two of you is going to be 31.1 yards. This is based on the angle of your shot. For this example, I used a 35-degree shot angle.
Given that whitetail have a propensity for ducking and turning when your arrow is in flight, it is important to get your yardage as accurate as possible to afford yourself the best chance of success. Those nearly yards of difference on your pins can make or break your shot.
The exact formula for finding the linear shot distance is: AD = LoS x cos(°). AD in this equation is the adjusted distance - or horizontal distance - you'll use to shoot. LoS represents the linear - or Line of Sight - distance between your and your target. (°) represents the angle at which you are shooting. Cos stands for cosine.
You will multiply the cosine of your shot angle by the line of sight distance to find your adjusted distance. Using the example above, it would work out to 31.1 = 38 x .819 (The cosine of 35-degrees is .819).
You won't realistically memorize the cosine of every possible shot angle, but you can use a reference guide to get as close as possible in your specific situation. If you are shooting a 3D or Total Archery Challenge event then you are free to do the math before each shot.
In a hunting scenario, it is likely not possible. If you are in a treestand, you can utilize the formula prior to opening day and take a general reference into the woods with you. If you are hunting on the move, such as a mule deer or elk hunt out West, then you can use a quick reference guide like this for help:
- 15° - multiply your LoS by .97
- 20° - multiply your LoS by .94
- 25° - multiply your LoS by .91
- 30° - multiply your LoS by .87
- 35° - multiply your LoS by .82
- 40° - multiply your LoS by .77
- 45° - multiply your LoS by .71
It may seem intimidating, but practice can change that. Climb up into your stand/saddle, shoot from an elevated porch, or stand at the bottom or top of a hill and practice the shots you expect to be taking in the field.
The more you work on angle compensation prior to the start of your season, the more it will come naturally to you. You may eventually know intrinsically how to adjust your aiming point without even moving your sight. Remember, "practice makes perfect."
Keep the following in mind and consider them when shooting at various angles. You will want to test and ensure that your sight is level along its axes - an incorrectly leveled sight can throw off your angled shooting. Based on your terrain or body orientation, you may have a natural desire to counteract your body position in how your hold your bow. This can lead to poor, imprecise shots.
Keep your scope level bubble in the center as much as possible. Finally, make sure to only adjust your body position at the waist when shooting up or down angles. This will ensure your shooting form remains the same. Bending at the shoulders or in your arms or neck will also result in inaccurate and inconsistent results.
To end on a good note, many rangefinders on the market today come with a built-in archery angle compensation system. This means, when you range, the angle your rangefinder shows to you is already the adjusted distance you need to shoot. If your rangefinder includes this feature, then you don't need to worry about the math we laid out above - but the practice and use tips still apply.
If you are in the market for a new rangefinder, or if you want to find one that features built-in angle compensation, then you can click HERE to view our current stock of rangefinders and find the one that will work best for you.