During the past several years, the US Army has focused considerable attention toward developing improved methods for breaching walls in the urban combat environment. A major thrust area is centered on finding improved methods to breach the toughest wall type that Army units are likely to face: a double (steel) reinforced concrete (RC) wall. One impediment to this effort is that the relationship between the contact explosive charge configuration and the quantity of concrete removed has not been thoroughly understood. The U.S. Army Engineer Research and Development Center has conducted a research effort to better define the effectiveness of various explosive charge configurations in breaching RC walls. This paper presents a discussion of results from this research.