Army Qualification with M16
Troops ZERO their rifles and receive instruction on a 25 METER range. I rarely see two ranges who agree on the nomenclature or procedure. The M16A2 has one elevation wheel marked one way, the M4 another, and the M16A3 yet another. Preliminary Marksmanship trainers rarely have access to good data about proper zeroing information and the range officers- who are frequently Wackenhut or other civilian agency employees, rarely have more.
They ARE usually very certain and forceful about what information they do have.
Soldiers QUALIFY on a 40-shot 400 yard pop-up range. They get Preliminary Marksmanship Instruction, Zero their weapons on a 25 Meter range off a sandbag from a bench, and then qualify.
The Army manual says that foot position in the foxhole is the first basic fundamental of marksmanship...so that's what they teach.
The Marines still spend weeks at the range and shoot across the course to 500 yards.