I have a Ruger AR 556 MPR for sale. This rifle is chambered for 5.56x45 or 223 rem. cartridges. It features an 18 barrel, rifle length gas block, muzzle brake, upgraded Ruger 2 stage 3.5# trigger, and factory upgraded Magpul M-LOK rails and furniture. It has a full 100% Ruger lifetime warranty. This rifle is in as new in box condition.