How do you assemble the barrel assembly to the receiver assembly of the M240?

Assembling the barrel assembly to the receiver assembly of the M240 is a critical step in ensuring the proper functioning of the weapon. The correct answer emphasizes the initial step in this process, which is to insert the barrel breach into the barrel socket.

This action is essential because the barrel breach must fit securely into the barrel socket to create a stable and safe connection between the barrel and the receiver. This ensures that when the firearm is fired, the gases generated by the ignited cartridge are directed properly through the gas system, and that there is no misalignment that could lead to a malfunction or an unsafe discharge.

By focusing on correctly inserting the breach first, you align the components for the subsequent steps, such as locking the barrel in place. If the breach isn't inserted properly, the entire assembly could be compromised, resulting in operational issues.

In summary, the correct choice underscores the importance of the initial alignment and connection of the barrel to the receiver, which is foundational to the overall assembly and function of the M240.