Which component on the M249 AR allows for adjustment of elevation settings?

The component on the M249 Automatic Rifle that allows for adjustment of elevation settings is indeed the elevation knob. This knob is specifically designed to enable the operator to adjust the rear sight elevation to target different ranges accurately. Proper elevation settings ensure that the rounds fired from the weapon hit the intended target at varying distances, compensating for the bullet's drop over distance.

The rear sight does contribute to aiming accuracy; however, its role is more about providing a reference point rather than facilitating adjustments for different ranges. The front sight assists in alignment but does not offer elevation adjustments itself. The receiver, on the other hand, houses the essential parts of the firearm and does not serve a direct role in adjusting elevation settings. The elevation knob is essential for effective shooting, enabling precision and adaptability in varied combat situations.