What is the main purpose of a gunner's data book?

The primary function of a gunner's data book is to record and calculate data essential for achieving effective firing solutions. This includes noting various ballistic parameters, environmental conditions, and any adjustments that need to be made based on the target's distance and movement. By maintaining detailed records, the gunner can quickly reference previous engagements and apply learned data to new scenarios, ensuring accuracy and efficiency in weapon employment.

Maintaining this data allows for better preparedness and responsiveness in combat situations, as it aids in predicting trajectory, calculating lead, and making necessary adjustments for wind and other factors. This practice is fundamental to maximizing the lethality and effectiveness of machine gun systems in diverse operational circumstances.