A soldier is tasked with measuring the muzzle velocity of a new rifle. Knowing the principles of projectile motion, he decides to perform a simple experiment at the indoor firing range. The soldier hangs a target a distance of d = 127 m from the end of the barrel. The rifle is mounted so that the bullet exits moving horizontally at the same height as the bullseye. After several trials, the soldier finds that the bullet strikes the target an average of 6.3 cm, below the bullseye.
What muzzle velocity should the soldier report to his sergeant?