Which component of the M119A3 helps in controlling the trajectory during firing?

The elevating mechanism is essential for controlling the trajectory of the M119A3 during firing. This component allows the crew to adjust the angle of the barrel, which directly influences the vertical trajectory of the projectile. By changing the elevation, the crew can effectively target different ranges and elevations as required for various firing scenarios. Proper adjustment of the elevation ensures accuracy and allows for effective targeting over varied terrain, making it a critical element in artillery operations.

In contrast, while the barrel itself is vital for directing the projectile, it does not allow for trajectory adjustments once it is fixed. The recoil system helps manage the forces generated upon firing but does not influence the projectile's path. The sights are used for aiming and targeting but do not have a role in modifying the trajectory during firing. Therefore, the elevating mechanism remains the key component in controlling the trajectory of the M119A3.