Hey,
Im new to this site and the world of the ar-15.  I have purchased two rock river ar-15s Post ban, and need to know all your suggestions about what you or the military does to customize it.
For example, what is needed for a light and what is the best kind. (ris system needed?)
also, what can you people tell me about ammo?
I live near austin tx and go to the saxet gunshow.  I purchase all my ammo from Just Ammo, all .233 (5.56) reloads.
Thanx,
Nolan

Welcome to pandora's box.  My recomendation is read up on the posts already made.  You may find your questions have been answered already.  Good luck and have fun with it.

I'd say the ammo will do just fine.  I have seen their booth at the fort worth show as well.  I like the ammo & should be fine.  I think you might shop around.  There is a ton of information in the ammunition section on the site.  I shoot nato 5.56,  but from what I have been reading will start trying other brands.  I like find a round I like & then buy 2000 or so rounds of that ammo to stay in a certain window with my optics.  But as I am fairly new to the AR, I still have a lot to learn about these fun guns.   by the way,  take your gun out to the range out on highway 71 torwards 620.  There is a good range that you can shoot at.  Has a 100-500yrd range with a large metal ram target...  

As for the flashlight-  would stay with surefire,  If you see a dealer at the saxet show that sells the surefire line ask him about boxes of surefire cr123 batteries.  25$ for 12, With the surefire logo on them.  You cannot beat that price...
Prosise    

http://www.san.surefire.com/cgi-bin/main.pl?pgm=co_disp&func=displ&sesent=0,0&prrfnbr=685

12 (123A) Batteries
(SF12-BB)
Price: $ 15.00

25$ for 12?
dealer is a rip off

Try the Search for posts on the equipment you are looking for. It was a big help for me after I bought my first AR. Welcome to the club.