EXHIBIT 32.2 CERTIFICATION PURSUANT TO SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002 In connection with the Annual Report of Engineered Support Systems, Inc. (the "Company") on Form 10-K for the year ended October 31, 2005 (the "Report"), I, Gary C. Gerhardt, Vice Chairman and Chief Financial Officer of ESSI, certify, pursuant to Section 906 of the Sarbanes-Oxley Act of 2002 that: (1) The Report fully complies with Sections 13(a) and 15(d) of the Securities Exchange Act of 1934; and, (2) The information contained in the Report fairly presents, in all material respects, the financial condition and results of operations of ESSI. Date: January 9, 2006 /s/ Gary C. Gerhardt - -------------------------------- Gary C. Gerhardt Vice Chairman and Chief Financial Officer