1600 is way too much. they usually go less than that with a 223 upper. colt is expensive and not top dawg anymore. you pay alot for the name. Id take a dpms and put 600 dollars in the bank. Also 7.62x39 uppers sometimes have a real problem with feeding in the ar. it has to do with mags usually. they can be finicky at times.
bottom line... nice weapon-too much money tho. And prices on ar's are dropping.