I am selling this for a friend. It is a Bushmaster Dissipator A2 upper with the M4 profile barrel. This is supposedly a hard combination to find and is lighter weight than a normal heavy barrel dissipator. It is in mint condition with 100 rounds through it. It comes complete with bolt, carrier and charging handle. He is selling because he decided to go with a scoped varmint upper. I can get photos for you if you need them. He wants $425 for it plus shipping.