I have an OCL OCM5 and 2 AB Raptor 10s with the reflex chamber. I am a huge fan of both of them. I really like the reflex design, both because the overall length added is less and because it gives a lot more room for the gas to go. 1 of the Raptors I have has the 5" reflex and it looks freaking huge, but it doesn't have "that" much added length. It sounds fantastic on a 300 PRC.