What's the proper or accepted method of loading/unloading an AR?  

Pull bolt back with charging handle.  While holding it back, press the bolt hold-open tab.  Bolt is now locked back.  Load one mag in te mag well.  Insert until it "clicks" in.  Then depress the bolt hold open tab and view the carrier and bolt slamming home.  Make sure the muzzle is pointed ina safe direction while doing this.  Take off safety, depress trigger.

When unloading an empty mag, the bolt will hold open automatically.  Depress the mag catch button, watching the mag come out.  Insert a new mag as described above and depress the bolt catch tab again.

If unlaoding a live round, manually, pull back on the charging handle and observe the shell ejecting.  Then holding the bolt back, depress the bolt catch holding it back.  Press the mag release button and take the mag out.

There you go.  

Don't forget to collapse the stock when done for easier storage!!!!!!!!!!!!!!!!!!!!!!

Thanks for the info.  If inserting a mag on a closed bolt, then pulling the charging handle chamber a round?

Quoted: If inserting a mag on a closed bolt, then pulling the charging handle chamber a round?

That can chamber a round.

-Generally the procedure is:
- Insert the mag
- Slap on the bottom of the magazine to insure seating
- Tug on the maga just to make sure it seated (this step is often debated - but I included it because many trainers teach it).
- Pull on the charging and handle and release it
- Press the foward assist (again another debated step - but I always do it)