So I have had a Rock River advanced tactical hunter for over a year and really like it. When I ordered it from Rock River I had them put on their quad rail and not the half quad that comes stock on the advanced tactical hunter. I now have added a bi-pod to this set up and from time to time I put on a forward grip, the problem now is I am running out of rail. My question to you all is which brand of quad rail would you suggest that would be an easy job to put on my Rock River and not break the bank. I would like one that will work for my needs. This is a hunting rifle that sees the range from time to time. I have seen these things range from 100 to 350 dollars. I recently purchased a daniel defense m4v5LW and really like the quad tube on it. Seems very well made and not huge and bulky like my rock river tube, its not cheap though. The rock river quad rail is to big around. I have sent e-mails to some companies but no response, I assume they have bigger fish to fry than dealing with me on a free float tube with whats going on in our country and the shot show. My rock river has a low profile gas block on it so I assume most would work. The length of barrel on my rifle is 18 inch stainless and would like to cover up as much of it as I can with a tube. I am looking at a 13-15 inch range of free float tube. I do want it to have 4 rails on it. Any of your experiences and/or suggestions would be appreciated.