The U.S. Army began its Master Gunner program in the late 1980s, as one of many post-Vietnam innovations and reforms. Army tank and mechanized infantry (equipped with M-2 Bradleys battalions) each had a "Master Gunner." This was a senior NCO whose job was to continually improve the marksmanship training for cannon gunners (120mm guns in tanks and 25mm autocannon in M-2s). The Master Gunner conducted training courses, worked with who had difficulty improving their skills, and sought out the best marksmen to become the next generation of Master Gunners.
A decade ago the army instituted a similar program for infantry weapons. In preparation for that, the army had selected some experienced airborne NCOs to develop a Master Gunner program for rifles and machine-guns. Soon each infantry division had 14 Master Gunners (one in each combat battalion, each brigade headquarters, and at division headquarters. Eventually, company size units for Master Gunners as well. Initially, these Master Gunners were told to improve the ability of troops to shoot at night. This was a period in which the army was putting more emphasis on fighting at night or, as the troops came to describe it; "owning the night." But after that was accomplished the Master Gunners began concentrating on marksmanship in general.
The Master Gunners not only created and ran marksmanship classes, but also sought out the exceptional marksmen. Not only would these be candidates for becoming Master Gunners, but they could be assigned to help soldiers who consistently ran into problems with their marksmanship. Such one-on-one training often solved the problem.
Master gunners also keep up on the latest marksmanship techniques and technology. Because of this the army found that anyone with normal vision and coordination could be taught to shoot accuracy if they were taught how to use the right posture and other techniques.
The Master Gunner program was eventually adopted for other weapons found in infantry units (rocket launchers, pistols, claymore mines, grenades and the many accessories). All this led to the use of more snipers and much greater combat accuracy for all infantry weapons. This has been noted by the enemy and allies in Iraq and Afghanistan, and other allies are also adopting the Master Gunner approach. Some countries already had a tradition of the Maser Gunner, but this was usually just the most accomplished gunner in a unit, who naturally shared his knowledge and skills with other gunners. The American approach not only selected and recognized the Master Gunners, but also created schools to bring newly recognized Master Gunners up to speed on the collective knowledge of all army Master Gunners.