Ok, I'm looking to get a bipod for prone shooting. Obviously Harris is respected, but Im not sure what I'm looking for. I CURRENTLY have standard carbine handgaurds (Bushy), but want to eventually get a free-float 4 rail set-up, so forward compatability would be nice. If i have to buy a temporary Picatinny rail, thats ok. I want a bipod that mounts all the way forward (I'm also planning on a front grip) w/ legs pointing forward and is fairly silent in use (no, I'm not a sniper wannabe, but why not do it right the first time?), and locks in position when not in use (wont come flopping down if you are running and bouncing about). From what I've seen, It looks like the Harris "L" model would work... Am I on the right track?

I have 2 L model that are the swiveling type. I really like them. the tension of the swivel is adjustable and all you need to mount one on a ff tube is a swivel stud. There are several options out there to accomplish that. So the Harris is very adaptable. My personal preference in heigth is the 9-13" model LS.

+1

Harris...all you have to do to put it on your current HG is get a $10 adapter (sorry no link, you'll have to search) which is basically a sling stud that mounts through one of the vent holes in your HG.

Once you get your railed HG, you have lots of options.  LArue and ARMS make throw lever adapters but they are kind of pricey IMHO.  I do not see a need for a QD bipod mount but YMMV.  KAC makes a very good one for around $35 but it uses a straight slot screw instead of throwlevers.  FWIW