Ryan Cleckner explains in a video from the NSSF why you should not cant your rifle – rotate it clockwise or anti-clockwise. Cleckner explains how canting your rifle in either direction will change the point-of-impact: “Not only does it move in the direction you’re rotating, but it also loses elevation as it rolls downward.” This can cause you to miss to one side or another: Cant to Left — You are going to miss low and to the left.Cant to the right — You will miss low and to the right. Cleckner demonstrates the effects of canting a rifle when engaging a target at 600 yards in this video. The shot POI is completely moved off the steel silhouette by a few degrees of cant, either to the left or right. The POI shift occurs because you are lowering and laterally shifting the scope sight line relative to the bore-axis. This changes your zero. David Tubb explained that “every 1 degree off on a rifle cant is about 6 inches of difference laterally at 1000 yards”. Position Shooting With Sling — Rifle Cant Issues
Cleckner’s discussion assumes the scope or sights is set to center, with the rifle plumb and level. This works in most situations, whether you are shooting prone from a front mechanical rest or sandbag, or a bipod. Many sling shooters tilt or cant their guns slightly inward, including David Tubb, John Whidden and others, because it allows for a more comfortable grip with the sling or better eye-to sight alignment. The angle at which the rifle is held can be effective, but the angle must be the same for every shot. Canting the gun is not a sin in and of itself. After you have confirmed your zero, the cant should be the same on every shot. You must maintain the exact same rotation for each shot, or you may experience the movement Cleckner describes. Consistency is key.
John Whidden, five-time National Long Range Champion, is holding a Palma rifle. John Whidden now shoots a match-rifle with an Anschutz Stock which he holds more upright, but still with a little counter-clockwise cant. John installed his iron sights at a slight angle to ensure that the adjustments were correct (and plumb), even with his canted grip: “While not obvious in the photo, the sights on the rifle are set up such that they are straight vertical and horizontal when I hold the rifle canted.” It is important to make sure that your scope or sights are both vertical and horizontal.
A bubble level mounted on a rail or scope is the best way to prevent inconsistent rifle canting. The Jialitte Scope bubble level is a very versatile and affordable product. This product has a 30mm inside diameter and an inner insert ring to fit main tubes up to 1” in diameter. The Jialitte unit has a low-profile in the middle and is nicely rounded. The user reviews are very positive. You could easily spend $35.00 or even more on a 30mm scope. This is only $8.79 (Cyber Monday special) on Amazon.
