Extended Range Guided Munition

[2] ERGM consisted of three major subsections: propulsion (rocket motor), warhead, and Guidance, Navigation and Control section.

ERGM is fired from the 127 mm (5-inch) 62-caliber Mark 45 gun Mod 4, at which point the fins would deploy and the rocket motor would ignite, lifting the munition to at least 80,000 feet (24 km), after which the canards would deploy and guide the ERGM to the target using GPS guidance.

Despite the long development time, the ERGM never worked as reliably as the older but significantly less expensive laser-guided M712 Copperhead.

[4] In February 2008, guidance components, rocket motors, and tail fins all failed in tests; Raytheon claimed they were testing specific functionalities rather than overall functionality and that they were "on the verge" of making the whole system operate reliably, but the Navy had lost confidence after years of issues and were no longer expecting a return on investment.

[5] BTERM was another U.S. Navy developmental round that included GPS guidance in an artillery shell; it too was terminated in 2008 after over four years of development by ATK.