20" heavy barrel upper by Olympic Arms, it came on my K8 Target/Match. I never shoot this upper so I am selling it. It has about 300 rounds through it and shoots well. It especially like 64 grain power points and 69 grain SMK's. Olympic Arms list the upper for $560, I am asking $400.00. I will entertain other offers/trades/partial trades. Feel free to offer, the worst I can do is say no. Currently SPF.