Upon further research including reading articles in the Varmint Hunter and various other publications, the results I was experiencing were validated. I concluded that cant does affect the point of impact, but by how much? The answer is not a simple one. If you have a very flat shooting projectile at short distances (and if your sights are aligned in this flat region) you may not be able to perceive much cant error. However, if you shoot long ranges at miniscule targets or shoot with a loopy trajectory as with airguns, blackpowder, or at extreme distances (400 to 1500 yards) you will be able to experience the problem yourself. Bow hunters, for instance, are keenly aware of cant error, since they need to adjust the elevation of the bow for long shots.
During a competitive airgun shooting, I found it impossible to use the two eyed, double vision bubble level setups that are prominently advertised in the shooting publications. I found it extremely distracting, if not impossible, to try to concentrate on the bubble level and the target at the same time. Furthermore, the simple 2D geometry explanations that are currently being published do not fully explain all the error that I was experiencing. As I tried to understand the problem, I became aware that the difficulty was a compounding of errors that makes it easy to misunderstand the real problem at hand. I now have an understanding of how the tilt creates these accuracy errors and have found an easier way to help eliminate them (see Cant Errors).
The problem became more apparent when participating in long-range varmint hunting. Varmint hunters today are so spoiled with their screaming fast, light weight projectiles. For the most part, they shoot relatively flat and, therefore, require very little elevation compensation out to about 300 yards. With the sport being what it is, we are always trying to push the envelope. Those of us that extend the range to 500 plus yards will see the effects of canting come into play. Thus, my quest began to develop a superior cant detecting device for shooters to eliminate the effects of canting on long-range shots.
After experimenting with many types of products and sensors, it became clear that the issue is not really a problem with the sensing mechanism at all. Rather the real issue is how the human brain interacts with the output information from the device. The various different products that show bubble levels mounted externally to the scope require that one eye or the other constantly re-focus between the distant target and the close bubble level, which visually results in some cross eyed double vision in your sight picture. Use of an external device requires the shooter to focus on the device and the target simultaneously. One scope manufacturer has a bubble level inside the scope. This still requires the shooter to look at and decide when it is centered. The last thing a shooter needs is something else to break his focus or concentration.
It quickly became apparent that we needed to get information to the shooter in some sort of a subconscious way. Yes, we thought about electric shock therapy but we couldn’t find a place for the large battery. More realistically, we concluded that using peripheral vision would be a better place to start. Our brains are wired to continuously take in information from our peripheral vision without affecting our primary concentration or central vision. Think of it like driving a car. We are constantly watching the road with our central vision. If a car approaches from the side or movement appears in the rear view mirror, we are aware that something is coming although we may not always know exactly what it is. As it turns out, our brains are especially adapted to accept information in our peripheral vision while still letting one concentrate on the central vision. (Really, I am not making this up – I went to the library to find this out!) After having gained this knowledge, the Microlevel® was developed to work accordingly.
As with any type of anti-cant device, there needs to be some sort of output to indicate the degree and direction to which you are “out-of-true vertical”. Likewise, a shooter needs to know when he is “dead-on-true vertical” requiring no correction. To indicate gross “out-of-true vertical,” we incorporated two red LEDs that are positioned symmetrically about a center green LED. Two yellow LEDs, also positioned symmetrically, indicate a lesser degree of “out-of-true vertical.” The green LED is situated in the center of the display and is illuminated when the firearm is “dead-on-true vertical.” It is not necessary to focus on the LEDs as you sense through your peripheral vision the color and the side on which the LEDs are illuminated (if other than green). The shooter then can rotate the firearm toward the central green LED, all the while focusing on the desired target. When the green LED is illuminated and the target is in sight you are good to go.
One problem with our peripheral vision is that we cannot make out fine details. We can see large changes in shape and movement and some color. The Microlevel® was designed with five very distinct indicators. The central indicator is green, and shows when the firearm is within a prescribed range of true vertical- say plus or minus 1 degree, as long as you are within the ‘zone’ the LED stays on (good-to-go). When you exceed the zone limit the yellow light comes on and the green light goes out. Likewise with the red indicator. The indicators are housed in a soft rubber eyecup close to the eye. The eyecup slides onto the ocular side of the scope but does not obstruct the full view of the scope image. By using peripheral vision, the shooter senses the color, adjusts if necessary, holds and shoots. With this, the shooter has achieved his goal of keeping his concentration on the scope reticle.