I just finished my first AR build- all parts are from Spikes Tactical with expectation to a Palmetto Armory lower parts kit. The BCG is from Spikes and has a chrome bolt assembly. It cycles brass ammo perfectly- however when I tried to shoot some steel cased I had a failure to fire on the 5th round. After reloading another magazine it happened again. I know the ammo is good because it functions properly in my other gun. Any ideas?