In this paper, we derive the rate bounds of a joint radar and communication system where the Comm-Radar is simultaneously detecting the target and receiving communication signals. We consider the case, where the communication signals also bounce off the radar target and are received alongside the radar signal. We show that the additional target bounces of the communication signals could potentially be used to improve the radar performance on direction estimation. To demonstrate the performance gain, we first propose an iterative-successive interference cancellation (iterative-SIC) scheme for the joint radar estimation and communication decoding. Then, based on the iterative-SIC scheme, we derive the joint outer bounds for the rate regions to characterize achievable estimation rate and communication rate performance. In addition, we present numerical results, which show the advantages of using the communication bounces.