the sniper may compensate incorrectly and the bullet path may be too high or low. As an example, for a typical military sniping cartridge such as 7.62×51mm NATO (.308 Winchester) M118 Special Ball round this difference (or "drop") from is . This means that if the sniper incorrectly estimated the distance as 700 meters when the target was in fact 800 meters away, the bullet will be 200 millimeters lower than expected by the time it reaches the target. Laser rangefinders may be used, and range estimation is often the job of both parties in a team. One useful method of range finding without a laser rangefinder is comparing the height of the target (or nearby objects) to their size on the mil dot scope, or taking a known distance and using some sort of measure (utility poles, fence posts) to determine the additional distance. The average human head is in width, average human shoulders are apart and the average distance from a person's pelvis to the top of their head is . To determine the range to a target without a laser rangefinder, the sniper may use the mil dot reticle on a scope to accurately find the range. Mil dots are used like a slide rule to measure the height of a target, and if the height is known, the range can be as well. The height of the target (in yards) ×1000, divided by the height of the target (in mils), gives the range in yards. This is only in general, however, as both scope magnification (7×, 40×) and mil dot spacing change. The USMC standard is that 1 mil (that is, 1 milliradian) equals 3.438 MOA (minute of arc, or, equivalently, minute of angle), while the US Army standard is 3.6 MOA, chosen so as to give a diameter of 1 yard at a distance of 1,000 yards (or equivalently, a diameter of 1 meter at a range of 1 kilometer.) Many commercial manufacturers use 3.5, splitting the difference, since it is easier to work with. It is important to note that angular mil (mil) is only an approximation of a milliradian and different organizations use different approximations. At longer ranges, bullet drop plays a significant role in targeting. The effect can be estimated from a chart, which may be memorized or taped to the rifle, although some scopes come with Bullet Drop Compensator (BDC) systems