Aspect mounted process using an built-in MILSTD 1913 rail piece for sighting techniques. Suitable for use With all the M203. only one data point, I picked up two or three salty utilized P&S M4 RAS's from Thoroughbred for $one hundred fifty ea. yeah, not KAC, but adequate for me. Posted https://ras-rail29628.get-blogging.com/30020903/the-5-second-trick-for-ras-m4