I am thinking I want to add a BiPod to my AR with an 18" Barrel. It has a short rail on the front of the lower forearm so I was thinking of mounting it directly to the rail. Most BiPods (Harris, etc) mount on a swivel stud. What are the BEST options for mounting a BiPod? I am thinking of the Harris 6-9" with detent legs and swivel option and it will be used on a bench and prone target shooting. Other suggestions are welcome as I have not purchased anything at this point. Thanks.