Flat-prime uppers are Geared up that has a Picatinny rail, which lets you put in a variety of optics as well as other add-ons. if you wish to include a pink-dot sight, a magnified scope, or every other type of optic in your AR-15, a flat leading upper is the way in which to go. additional evaluation on the M14 and M16 was carried out by an imparti