Re: Which monopod?
I have the accu-shot BT-12 with the Quick Knob on my DPMS/PRS rifle and I'm very happy with it. I chose that model because it can be folded out of the way quickly when it is not needed. In my opinion the quick adjust knob is well worth the extra $.
I will say that there is not as much height adjustment as some people might like (about 1" between highest and lowest), but for my needs, it has been more than adequate. Just be sure it has enough elevation for you.
Good luck.