I have a never mounted DPMS Mk12 .223/5.56 barrel for sale. I forgot I ordered it and nearly a year later, here it is. It has a single rail gas block mounted on it (it came that way). This barrel is very accurate according to multiple reviews of it. The barrel is Teflon coated black, 416 stainless steel, heavy contured, 1/8 twist, and is threaded 1/2x28 (standard .223/5.56 threads) for what ever muzzle device you want. On the DPMS website it says the stripped barrel is $179. I paid $199 with the gas block as that was the only way to order it a year ago. Here is a link to the barrel on midwayusa.com. http://www.midwayusa.com/product/43...contour-1-in-8-twist-18-stainless-steel-black Price is $175 firm.