[Cobra642]

I recently purchased a Bushmaster M4A3 as a birthday present to myself and had a question for the experts. I haven't used a .223 round much since basic training in 1981 and don't know much about commercially available rounds.
My questions are:

1) What's a good brand/type of ammo for zeroing and basic range shooting, and

2) What's a good brand/type for having on hand for the next suburban neighborhood insurrection, or for that matter

3) What are brands/types to stay away from.

Thanks in advance.