ARMY AL&T


The Army’s solution is the new M855A1 Enhanced Performance Round (EPR). This round offers better performance than the M855 against all targets likely to be engaged with small arms. This is quite a feat, considering the long-standing solid performance of the M855.


While it’s true that a number of bullets (such as armor-piercing bullets) can penetrate hard targets well, they don’t provide the needed effects against soft targets. Conversely, some bullets (such as hunting rounds, hollow-point, and other bullets) work well against soft targets but can’t penetrate harder barriers. Nor do hollow points meet the Army’s requirement to adhere to the Law of War, defined as “[t]hat part of international law that regulates the conduct of armed hostilities. It is often called the ‘law of armed conflict’ ” (DoD Directive 2311.01E, DoD Law of War Program). Even today, we have found no other round—other than the new EPR—that can outperform the M855 as a capable, general-purpose round.


Why the M855A1 Excels So what makes the EPR so good? It uses the same components as the M855—a jacket, a penetrator, and a metal slug. But the new round contains some subtle changes (see Figure 1). The copper cup, from which the jacket is formed, is reverse-drawn, the oppo- site of how the M855 jacket is drawn. The hardened steel penetrator is almost twice as heavy as the one used in the M855 and is fully exposed instead of hiding beneath the softer copper jacket.


The slug is made of copper, making the projectile nonhazardous to the environment while delivering needed performance. Since the EPR is similar to the M855, the Army can use the same manufactur- ing equipment


The EPR provides the same effects when striking its target, regardless of the angle of yaw. This means the


EPR provides the same desired effects every time, whether in close combat situations or longer engagements.


now used for the M855, providing additional savings and large-scale manu- facturing capability. Once the M855A1 replaces the leaded M855, it will reduce the amount of lead in production by approximately 2,000 metric tons yearly, based on the amount now used to make the M855.


There are three main areas in which the new round excels: soft-target consis- tency, hard-target penetration, and the extended range at which it maintains these performance improvements.


This is not to imply that the EPR increases the maximum effective range of the M4 or M16. Its trajectory matches the M855’s, which aids in training, less- ens the need to re-zero the weapon, and allows it to link to the current tracer round (the M856) for eventual use in the M249 SAW. So while the maxi- mum effective range does not increase, effectiveness at range does, meaning the round greatly extends the range of desired effects along its trajectory.


The Army tackled the consistency issue by focusing on the yaw of a projectile and how differences in yaw can influ- ence results when striking soft targets. The M855 round, similar to the Army’s M80 (7.62mm ball round), is a “yaw- dependent” bullet. As any bullet travels along its trajectory, it “wobbles” in both pitch and yaw, causing the projectile to strike its target


at different attitudes with virtually every shot.


The M855A1 Enhanced Performance Round offers better performance than the M855 against all targets likely to be engaged with small arms. (Photo courtesy of PEO Ammo.)


For a yaw-dependent bullet such as the M855 or M80, this results in varying performance, depending upon where in the yaw/pitch cycle the bullet strikes its target. For example, at a high angle of yaw, the M855 performs very well, transferring its energy to the target in short order. At a low angle of yaw, however, the bullet reacts more slowly, causing the inconsistent effects observed in the field.


The M855A1 is not yaw-dependent. Like any other bullet, it “wobbles” along its trajectory. However, the EPR provides the same effects when strik- ing its target, regardless of the angle of yaw. This means the EPR provides the same desired effects every time, whether in close combat situations or longer engagements. In fact, the U.S. Army Research Laboratory (ARL) veri- fied through live-fire tests against soft targets that, on average, the M855A1 surpassed the M80 7.62mm round. The 7.62mm, although a larger caliber, suffers from the same consistency issue as the M855, but to a higher degree.


Hard-target performance is a second area where the EPR really shines (see Figure 2 on Page 35). The exposed, heavier, and sharper penetrator, along with a higher velocity, allows Soldiers to penetrate tougher battlefield bar- riers than is possible with the current M855. Although it’s not an armor- piercing round, the EPR can penetrate 3/8 inch-thick mild steel at distances approaching 400 meters (based on the range at which 50 percent of the rounds can pass through the barrier). The M855 only penetrates this material out to approximately 160 meters. Not only


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