I have two of them. Both are15". One is on a 18" barrel 6.5 Grendel and the other on an 18" 223. I really like them, light and strong with front and rear holes for sling attachment. Only problem I had was both of my barrels are Oden Works with their tunable gas block. Both gas blocks just barely touched on the inside. I have a flex wand that fits on my Dermal tool and I could reach up inside and ground a little so the block would clear and everything worked fine.