I will buy a complete upper also. What to look for barrel wise ect. What about the bolt carrier , what is good what should I stay away from. Charging handle as some 20 to 60 does it really matter. What is good cheapmags. Gun for range and defence. Never owned a AR before. Sights , thinking reflux I think ts called not sure I wantva scope. Im on a lower cost budget looking for sales/blems ect but want a good shooting reliable gun.