it is a Colt 1/7" 16" chrome lined bore and chamber barrel with the integral muzzle brake with a Les Baer flat top upper and a Hyperform carbon fiber hand guard. It is about a light as a 5.56 upper can be. I bought this from a team member at the last KY ARFCOM shoot (KY_Bob), I shot it about 50 times and it worked very well. I was going to use it as a deer rifle but decided to go a differnt route, I was going to use the barrel in a 14.5 inch build but I dont have the heart to scalp this awsome upper, so my loss your gain. There is some small amount of paint on the upper from the past owner but it will come right off with some cleaner.