Which adjustment method involves a single round for a quick response but needs an experienced observer?

The adjustment method that involves a single round for a quick response and requires an experienced observer is One Round Adjustment. This technique is designed for situations where immediate effects are necessary, allowing the observer to place a round quickly on a target to gauge its effectiveness. The trained observer assesses the impact of this single round before calling for any further fire, which hinges on their expertise to interpret the results and adjust accordingly.

The reliance on the observer's experience is crucial; they must accurately analyze the situation and determine whether further rounds are needed, or if adjustments should be made based on the initial round's impact. Their proficiency enables them to make rapid decisions, a key component in high-stakes environments where timely responses can significantly influence the outcome of operations.

Other methods, while valuable in different contexts, may not provide the same immediacy in response or require multiple rounds and adjustments, making them less suitable for urgent situations.