M855A1 Enhanced Performance Rounds 20 Rounds

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 (SS109 Green Tip) only penetrates this material out to approximately 160 meters.

Evolution of the M855A1 Enhanced Performance Round | Article | The United States Army