The barel says 556 and no markings on the upper that I could find.Do you have a picture of the other side of the upper and any marks on the barrel itself? That looks like a post ban lower, but the match targets Ive seen were 20 inch barrels. If it was a complete post ban it wouldnt be threaded. I have been wrong before though..lol..if its all Colt (except for the handguard) thats a great price