Facet mounted technique by having an built-in MILSTD 1913 rail piece for sighting techniques. Suitable for use with the M203. Posted by BRAD on 23rd Jan 2020 Wonderful solution, matches just like a glove, strong, sound and may take a beating. Took me a minute to set up it mainly https://kacras09443.blogspothub.com/29008442/the-definitive-guide-to-ras-m4