Convictions of f conspiracy to distribute and possess with intent to distribute heroin within 1,000 feet of a public housing complex, 21 U.S.C. section 846, 841(a)(1) and (b)(1)(A), and section 860, use or possession of a firearm in furtherance of that drug trafficking offense, 21 U.S.C. section 924(c)(1)(A)(i), (ii), (iii) and 18 U.S.C. section 2, and use of a communication facility to further a drug conspiracy, 21 U.S.C. section 843(b), are affirmed where, although the District Court did violate Evidence Rule 403 when it admitted certain evidence, nonetheless, given the overwhelming amount of other evidence of guilt, that the error was harmless.