We discuss recent theoretical and experimental work concerning the phase jump instability in the He:Ne ring laser gyroscope. The exact solution to the deterministic third-order equations for the laser yields an expression for the phase difference between the two counterpropagating modes. This phase difference can be constant monotonically increase oscillate be unstable or exhibit discontinuities. Experiments and computer solutions of the stochastic laser equations show corresponding phase jumps which can be very rapid but not truly discontinuous. We discuss the behavior of the phase difference and of the timeaveraged beat frequency between the two modes with and without the effects of laser noise.