Best setup for the AR

Hey guys I have been a AR fan forever and I have my class setup as follows

AR
MAGNUM
FRAG
PROMETHIAN VISION
SHIELDING (increase shield recharge)
DEXTERITY

Now I am coming up short sometimes and I feel my setup could be improved to help my AR preform better.

So does any one have some tips on what I could use to help my AR a bit? I feel I should change the AA to something else but I dont want to just waste my points on some useless stuff (thruster pack).

Any advice on makeing the setup better would be appreciated.

I ripped it up in Regicide today with an AR.

My setup: AR, Plasma pistol, Promethean vision, AA recharge perk, dexterity.

Cool I will try your setup out. This AR is the best one i have seen in a halo game it can compete at range. Unfortanatly today it was tryhards all camping and spaming there dmrs/brs in tag teams