Different to the contraction of cannot, one definition of cant relates to something that is slanting or tilting. Regarding long range shooting, cant is a common cause of inaccuracy.

Caveat: I’m not writing from a position of authority. I picked up a new hobby, and writing short articles is a way to document my learning, and encourage further study.

To understand how cant affects accuracy, we’ll simplify a scenario. Imagine perfect shooting conditions, zero wind. The only forces acting on your bullet are gravity, and air resistence, making trajectory prediction easier. All you have to do is adjust for the distance, and aim true. Yet surprisingly all your shots are landing to one side of the bullseye, and a little low. The grouping is consistent, so it’s probably not due to the rifle, or your aim. There’s no wind to be pushing your shots off course, what can it be? Perhaps you aren’t holding your rifle perfectly vertical, and cant is the cause of the inaccuracy.

Let’s appreciate how rifle aim works. Your aim, from your eye, through the sights to the target, is a straight line. The barrel sits underneath your line of aim, pointing slightly up, so the bullet is thrown in an arc at the target. Your ballistic calculations work on the assumption that the plane created by your line of aim, and the line of the barrel is perfectly vertical. Any deviation from vertical will cause some degree of inaccuracy, and this error grows with distance - this is cant.

When the rifle isn’t held vertically, the barrel releases the bullet on a slight angle. Such a trajectory means the bullet won’t reach the same height, and impact low on the target, and to same side of the cant (there are scenarios where canted shots may impact level, or slightly high, on the target but they involve significant wind adjustments).

Depending on your rifle setup, cant can manifest in a variety of ways:

  • rifle cant

    You aren’t holding your rifle perfectly vertical.

  • sight/scope cant

    When you set up your sights, you didn’t align them vertically above the barrel (relative to how you hold the rifle).

  • reticle cant

    Within your sight or scope, the targetting reticle may not be sitting cleanly vertical.

That’s why it’s valuable to have a gunsmith check your setup. They will have equipment to identify alignment issues.

Research has shown that even experienced shooters struggle to identify up to three degrees of cant. At long range, three degrees of cant will make you miss the target completely. So how does one solve the issue of cant? Most precision rifle setups will have a spirit level integrated into the sights. The bubble provides some feedback to the shooter regarding the angle of their rifle.

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By aTarom - Own work Cámara: DiMAGE 7Hi ISO: 100 Tv: 1/2 Av: 9.5, Public Domain, Link