Just got my first AR and it's also my first rifle. What grain ammo do I use for what? (Plinking and Self defense) Also what's the deal with using Steel case ammo like Wolf? If I have to replace something  that wears out after 20K rounds I will have save enough to almost replace the whole rifle by then. What would be the harm in using steel case over brass? Know I do understand that for self defense I may have to spend alittle more.

Thanks for any help.

Did you read ANY of the tacked threads at the top?  Particularly the one that said 'READ BEFORE POSTING '?

Ammo-Oracle

That should clear up all your immediate questions.

FOREST you are an asshole!