Save some money,and buy a Kel-tec PLR16 223 pistol. It is a whole lot lighter,and easier to handle/carry than a AR pistol and it uses any AR magazine,and they are pretty accurate shooting guns.
SIG P556 SWAT --
They run about $2K w/ the SIG STS 081 Mini Red Dot
I'm usually all for Sig - but really the Keltec PLR16 is a great rifle reduced to pistol size. I really can't imaging having much use for your $ to poor in to a .223 pistol - so go cheap and have fun.