of the M80 projectile and is not an accurate comparison between the two cartridges. The US Army Picatinny Arsenal stated that the new M855A1 offers improved hard target capability, more consistent performance at all distances, enhanced dependability, improved accuracy, reduced muzzle flash, and higher velocity compared to the SS109/M855 round. Further, the Army stated the new M855A1 ammunition is tailored for use in M4 carbines, but should also give enhanced performance in M16 rifles and M249 light machine guns. The new 62-grain (4 g) projectile used in the M855A1 round has a copper core with a 19-grain (1.2 g) steel "stacked-cone" penetrating tip. The M855A1 cartridge is sometimes referred to as "green ammo" because it fires a lead free projectile. It is not necessarily more lethal than the SS109/M855, but performs more consistently every time it hits a soft target and retains its performance at longer distances. The EPR can penetrate a thick mild steel barrier from an M4 at and from an M16 at . Compared to the SS109/M855 the M855A1 muzzle velocities are somewhat increased to (+) for the M16 and (+) for the M4 carbine. Ballistics for both rounds are similar and do not require weapons to be re-zeroed, but if they are the EPR can be slightly more accurate. The steel-tip penetrator of the M855A1 is noticeably separated from the jacket of the bullet and can spin, but this is part of the design and does not affect performance. The M855A1 costs only 5 cents more per round than the M855. The M855A1 bullet has a greater length than the SS109/M855. Because steel and copper are less dense than lead, the bullet is lengthened inside the case to achieve the same weight as its predecessor. The longer bullet and reverse-drawn jacket make it more stable and accurate in-flight. Its steel tip is exposed from the jacket and bronzed for corrosion resistance. The tip is serrated and larger than the M855's steel tip. The M855A1's bullet composition, better aerodynamics, and higher proof pressures give it an extended effective range for penetration and terminal performance. While effectiveness at different ranges is increased, the M855A1 does not increase the effective ranges at which weapons are expected to hit their targets. The Enhanced Performance Round was made to nearly match the trajectory of the M855 to aid in training consistency—the SS109/M855 ballistic coefficient (G7 BC) of 0.151 was improved to