What does it mean to sight-in a rifle?

Sighting-in a rifle refers specifically to the process of adjusting the rifle's sights or scope so that the bullet impacts at a known distance where the shooter is aiming. This is crucial for accuracy, as it ensures that when the crosshairs of the scope are aligned with a target, the bullet will actually hit the target at that range.

In practical terms, the shooter typically fires several rounds at a target from a set distance and makes adjustments based on where the bullets hit in relation to the point of aim. This procedure is essential for anyone aiming to hunt or shoot accurately and effectively, as it establishes a reliable point of impact.

The other options describe different actions or concepts that do not directly align with the precision needed to effectively sight-in a rifle. For example, changing from open sights to a telescopic sight is a component of the sighting process but does not capture the full meaning of sighting-in, which emphasizes the adjustment of aim to ensure accurate shooting. Looking down the barrel or aiming at cans does not involve the necessary adjustments for accuracy at a designated range, which is central to the concept of sighting-in.