I have a sport and am pleased with and yes ammo is a big problem for blowing up AR's . Seems like fed winny and GA have all run large batchs of junk ammo . SW makes all there metal work in house too. If you will watch that video you can see after many shoots he had a round chamberd it did seem to fire but no recoil or bolt movement and may have been no powder ,just a primer, He then ejected the round, chmabered another round and fired, boom. His fault.