Rock River Arms R3 3-gun competition 223 upper for sale AR0700 $650 Or Best Offer (OBO). Will discount for USPS money order. For sale is BRAND NEW 1 Rock River Arms AR15 3-gun competition upper receiver, model number AR0700. Specifications as follow: R3 Competition Upper Half Flat Top Upper Receiver. 18" Fluted Stainless 1:8, 223 Wylde Phosphate BCG. Upgrade to RRA Chrome available. RRA Directionally tuned and ported muzzle brake RRA TRO-XL Free Float Modular rail system Low Profile gas block. PM or call 773-980-7037 Located in Glenview, IL; but sorry no local pickups.