A resonant micro optic gyro (RMOG) is a promising candidate for applications requiring small, light and robust gyros. A high-performance RMOG requires a low-loss micro-ring resonator, and thus a resonator having a high finesse. We experimentally create a new record for high-finesse micro-ring resonators by using 30-cm long low-loss fiber coils laid into the V-groove on a silicon substrate. Both the simulation and experimental results indicate that the 30-cm long microring resonator is sufficient to build a tactical-grade RMOG. Experimentally, a bias stability of 0.046°/s in 1800 s with an integration time of 1 s is successfully demonstrated.