They sell a TLR-1 Long Gun kit that includes the light and the additional accessories, namely the replacement battery door/switch assembly (available here on Amazon) that adds the remote/tape switch socket, the tape switch, and some stuff for rail mounting.

I purchased a long gun kit and put it on an AR, it works decently well, although not nearly as good as my Surefire 640DF as far as throw (which should be obvious).