That's a standard 15-22 with custom replacement of the barrel nut and hand guards, with a screw-on FSP/gas block attached to the barrel. One of these days I'm going to do the same, as I really prefer this look over the pseudo-freefloat look that S&W ships, and it would match my 5.56 much better.
However, the 15-22's factory configuration is a perfectly functional setup, and I've got far too many other things to blow time and money on right now.
(It still looks badass Brett...)