How important is it to keep your bow level when shooting? The answer is that it is very important if you care about the arrow hitting where the pin is. These days most sights come with the option of a level that can prove to be a valuable tool; there are also a few tricks to help draw and keep a bow level.
Of course not all cant is bad, that is if you are shooting without a sight. Many traditional shooters and even those shooting a compound without a sight find that a little or even a lot of cant is a more natural way to shoot when aiming instinctively. When I shoot a recurve I tend to have my bow canted 35-40 degrees and it feels perfectly natural.
What causes a bow to be off of level? There are several causes: some people naturally hold at and angle (cant), shooting on a slope tends to cause the shooter to lean with the hill, medium to strong winds, bows that are not balanced properly, etc. The key is to know when there is a chance of being off center (which is basically always, though the above listed situations magnify it) and how to prevent and correct lean.
I took the Destroyer 350 out into the field to find out just exactly how much of a cant produced noticeable results in the accuracy of my arrows. I purposefully canted my bow varying degrees and shot from several distances to see where my arrows hit compared to the aiming spot. At 20 yards with a cant of up to 3 degrees or so there wasn’t much difference in impact, but when the cant hit 5 degrees the arrows were noticeably off of center, though mostly in-line vertically. Moving further back increased the amount of inaccuracy significantly, even when the bow was tilted less.
The following image shows the typical results of an approximately 3 degree cant at 40 yards:
Three and a half inches to the left and an overall lower grouping vertically is a fairly significant amount. I shot groups similar to this very consistently several times before I was satisfied with the results. In a 3D shoot where every line counts, this is certainly a large enough distance to affect a final score. When hunting in the field this could also be the difference between a kill shot and a very long trailing job that may end up in a lost deer.
The best way to prevent lean/tilt/cant is to use a level and to use it on every single shot. Even when it feels that you may be on level ground, there may be a slight slope and that is all it takes to mess with your center of gravity and cause the bow to be off of center. When shooting on steep hillsides many shooters find that purposefully leaning into the hill while pulling the bow back will help the body and bow come to center much easier. Another method is to hold the bow up, level it before drawing and attempt to keep it level through the draw. I personally find that trying to level my bow at full draw is much more difficult than using one of the aforementioned techniques to get the bow to level at the draw.
Whatever the case or cause, having a bow that is off of level will cause some inaccuracy. How much is determined by the severity of the cant and the distance to the target. Take steps to prevent any lean and learn to keep that bow level!