Which of the following best describes the purpose of the receiver in a machine gun?

The receiver of a machine gun serves a fundamental role by holding both the barrel and the firing mechanism, which are critical components for the operation of the weapon. As the structural frame, the receiver includes the necessary housing for the bolt and firing pin, ensuring that these parts function correctly during the firing process. This centralizes the components of the machine gun, allowing for efficient operation and maintenance.

The barrel needs to be securely attached to enable safe and accurate firing, while the firing mechanism must be properly aligned to ensure reliable operation. Without a well-constructed receiver, the machine gun would fail to function as intended, compromising its effectiveness in various operational scenarios.

Other options, while related to aspects of machine gun operation, do not accurately capture the primary function of the receiver itself, which is critical for assembling and holding essential parts together.