Diamondback Firearms Barrels, 6.5 Grendel, 18, 1:8 Twist, Black Nitride, Finish, Mid Length Gas System, Threaded 5/8-24, Fits AR Rifles 65M18M50B8R At Diamondback" they are able to produce barrels that meet the shooters requirements. Their barrel blanks are made from premium materials and machined using some of the finest equipment on the market. Diamondback has several high-quality CNC machines that are used for a variety of purposes. With their machining capabilities" they can serve industries including self-defense" medical" aerospace" military" and more. With a mid length gas system and medium contour" their 6.5 Grendel barrel is a perfect example of modern day barrel making. Made from 4150 Chrome Moly steel with a Black Nitride finish" this button rifled barrel is 18" in length and offers a traditional 11 degree target crown.