Buy a Smith & Wesson M&P 15OR you won't regret the purchase and you can count on top quality parts, machining, rifiling and fit and finish. Along with a lifetime warranty from an American company. Then you can add to it what you want.
Smith & Wesson M&P 15 Optic Ready Carbine Part: 811003
http://www.smith-wesson.com/webapp/w...layErrorView_Y
Average retail price on this Carbine is $800. Get one!