Which procedure involves placing a boresight inside the gun barrel?

Boresighting is the procedure that involves inserting a boresight into the gun barrel. This practice is essential for aligning the sighting system of the weapon with the bore of the barrel. By ensuring that the sight is looking exactly down the center of the barrel, boresighting helps to improve accuracy and ensure that the projectile will hit the intended target when fired.

When a boresight is used, it provides a reference point that allows the gunner or technician to make necessary adjustments to the sighting system. Proper boresighting minimizes the need for extensive firing adjustments later, saving time and ammunition during the calibration process.

Other terms like tramming, calibration, and alignment are related but serve different purposes. Tramming refers more to leveling and aligning equipment rather than specifically inserting a tool into the barrel for alignment purposes. Calibration typically involves adjusting the measurement systems or instruments to ensure accurate readings, while alignment can refer broadly to ensuring different components of a system are set correctly but does not specifically involve a device being placed inside the barrel itself.