One thousand six hundred meters was a somewhat too far for a sniper.
At this distance, it wasn't impossible to hit a person, but when the spread of the bullet was much larger than the human body, hitting became a matter of low probability. Simply put, it was a matter of luck. If you were lucky, you hit your target; if not, it wasn't considered bad luck, just normal.
To change this situation, one not-so-practical solution was to increase the caliber of the rifle and enhance the firepower, allowing the bullet's trajectory to maintain its linearity for a longer duration. However, the large caliber sniper rifles had essentially reached the limit of what a human could withstand. Even if one could bear the recoil when firing, making the rifles bigger would negate the ability of a soldier to carry it into combat, thus defeating the purpose of the weapon. Hence, despite the existence of 14.5 mm caliber anti-material sniper rifles, the mainstream remained at 12.7 mm.