Computed settings for 105mm howitzers should account for the elevation difference between the gun location and target. The Tay Ninh area was so flat we eliminated elevation difference which made calculations less complex and faster. Properly calculated, done with correct information for all variables, the gun settings calculated should land the first round on target. As that was impossible OUR goal was to land the third round on target. If the first round (marker round) was close to the target and the observers visual line to the target is correct, adjusted settings should bring the second round closer. Corrections based on the second strike should yield corrected gun settings that put the third round on target. A knowledgeable observer is needed to provide the location of each landed shell for successfull artillery fire. That can be a dangerous job! Read the full story. https://vietnamsoldier.com/accurate-artillery-fire-2/