A coupled-mode theory of overmoded, cylindrical metal Bragg-reflectors is presented. The first-order Bragg coupling constants are derived for TE → TE, TM → TM, TE → TM, and TM → TE mode conversions. Reflectivities and transverse mode

-factors are computed for a Bragg-reflector resonator. The results illustrate important competition effects between nearly-degenerate-transverse-modes occurring within both the Bragg-reflectors and the resonator.