I have for sale or trade a Colt SP1 upper that has had the carry handle & front site milled off professionally & a ssHBAR w/aluminum handguard installed and a flattop rail installed on the reciever. The barrel is 24" long and the upper still has bayo lug,A2 flash hider, complete with ch/bc/b. It is in excellent condition w/only minor handling marks on for arm. I will trade for a Colt A3 upper 16" or sell for $300. All work that was done on this upper was done by a professional but I will give a three day inspection period.