Which of the following principles involves the positioning of machine guns for maximum coverage?

The principle that involves positioning machine guns for maximum coverage is actually best represented by the concept of interlocking fire. This principle emphasizes the arrangement of multiple machine guns such that their fields of fire overlap. When machine guns are positioned to interlock their fire, they create a more comprehensive coverage area, ensuring that opposing forces are effectively engaged from multiple angles. This setup enhances the overall firepower and defensive capabilities of the unit, making it difficult for the enemy to advance or maneuver.

While sited in defilade refers to positioning machine guns in a way that protects them from view and fire, it does not inherently maximize coverage in the same way that interlocking fire does. Other principles like economy of ammunition focus more on conserving resources rather than coverage, and mutual support is indicative of units providing security and assistance to each other, which can sometimes help in coverage but is not its primary goal. Therefore, interlocking fire is the correct principle that directly relates to maximizing coverage through strategic positioning.