I have owned a Colt AR15 since the late 80s or early 90s but can't remember exactly when I aquired in a trade for a Remington 870 trap. the specs are as followed---Receiver AR15-A2 Govt.Model Cal .223 Ser. GS00841---Barrel is marked ONP 5.56 NATO 1/7. There is no bayonet lug and the finish is a light greenish-grey smooth parkarized. The mag that came with the gun is aluminum with the same finish and marked on the floor plate Parsons Precision products Parsons Ks. USA. I am not really into AR rifles and am giving it to my son. I would like a little history on this rifle and figured this would be the best source. A friend of mine said it was a Model 6550 whatever that is. Ballpark value in very good condition and shot very little. Thanks in advance for any info.