Effects On Ammunition

The bullet begins to fall as soon as it leaves the muzzle of the rifle. The maximum speed or velocity of the bullet is at the muzzle, so it also begins to slow down as soon as it is fired. Figure F-l, page F-2, shows that the Ml93 ammunition drops 24 inches in slightly over one-third of a second. The chart shows the amount of drop relative to the departure line or bore line at 25-meter intervals and the time required to reach each range distance.

At first, the bullet travels fast, covering the first 25 meters at an average speed of almost 2,200 mph. The last 25-meter segment shown in Figure F-l (275 to 300 meters) is covered at an average speed of about 1,450 mph. Gravity causes the rate of drop to increase as flight time increases. Since it takes the bullet more time to travel as the speed slows, the effects of gravity and wind increase as the range increases. Each band on the chart represents 25 meters —the width of the band indicates the length of time it takes to travel that 25-meter segment.

The drop in inches from the rifle bore line is shown on the left side in Figure 1. In this example, finding the number 5 on the left side of the chart and going across to where the bullet is indicated shows the bullet has dropped 5 inches when it reaches 150 meters and has taken .17 second (column at right) to arrive. The bullet drops 2 inches more between 150 meters and 175 meters, and it takes about .03 second to travel that extra 25-meter distance. MI6A1 and M193 ammunition.

Bullet drop. The bullet is affected by gravity just like any other falling object. Even though the bullet is traveling fast, once it has been fired from the rifle, it falls to the ground as though it were dropped by hand. Figure F-2 shows how much the bullet drops from the bore line of the rifle. If the bore of the rifle were to be lined up on a 450-meter target (the same as looking through the bore and aligning the bore with the target), the bullet would hit 64 inches below the spot where the bore was pointing. This much drop is important if soldiers are to be effective marksmen.

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