For reliability, accuracy, and good quality in a precision target AR I'd go with a RRA National Match A4 AR
HERE. You could get it with or without sights for about $1,250. Add to that an excellent Nightforce NX8™ 4-32X50 F1 Scope
HERE for about $2,150 and you've got a killer combo totaling $3,400 with $1,600 left for mags, a sling and bag, and lots of precision ammo to train with.