Hello guys, I have for sale a great Upper in good condition. Whole assembly is in great overall condition. Barrel is a lightweight pencil profile with a 1/7 twist and a mirror-shiny bore. Came with a half moon Colt bolt not sure if it's original to this specific upper. From what I read this is the only bolt that will work with those old Colt lowers with the sear block on them. Works exactly like any other carrier would if you want to use it on another AR. Seen some folks selling the whole gun for 4 figures so figuring this is a fair price. If you have any questions please let me know. Price is shipped