What must be done once a range bracket has been split and the last fired round is within a specified distance?

When a range bracket has been split and the last fired round is within a specified distance, it is critical to send refinement corrections to the Fire Direction Center (FDC). This step allows for precise adjustments based on the observed impacts of the previous rounds, ensuring that subsequent fire missions are more accurately placed on target.

Sending refinement corrections is essential in the artillery process because it enhances the reliability of the targeting data and helps in achieving the desired effects on the target. Without these corrections, the risk of additional errors in range and deflection could persist, potentially leading to ineffective fire or collateral damage.

Other actions, such as ending the mission or verifying the range again, do not directly contribute to improving the accuracy based on the current information from the last fired round. Adjusting the sheaf, while important in some contexts, is less relevant in this specific situation compared to making the necessary corrections based on observed data. Thus, refining corrections to the FDC is the appropriate action to ensure improved fire effectiveness.