What kind of adapter do I need to mount a Harris bipod to a KAC RAS rail? Thanks

There are several.

The cheapest is the Fobus/First Samco one:

[img]http://www.cmmginc.com/cmmg_images/tbl_images/accessories_images/Universal_Mount.jpg[/img]
(photo courtesy of [url=www.cmmginc.com]CMMG[/url]

But the ones really worth the $ are the KAC one:

[img]http://mstn.biz/images/Slings%20and%20mounts/98060%20bipod%20adapter.gif[/img](sorry for the small image, it was the only one I could find)

& the ARMS one:

[img]http://photos.ar15.com/ImageGallery/IG_LoadImage.asp?iImageUnq=3849[/img]

Both the last photos are courtesy of Wes Grant at [url=www.mstn.biz]MSTN[/url].

The first two examples don't require any modifications to the Harris, but the last one (the one I use) replaces the retention assembly for a much better platform, methinks.

Hope this helps.