Look under "metals" in the phone book the stuff you buy at the hardware store is junk. It does not have the alloys to withstand our type of abuse, its far to soft it scratches easy and bends. It might work ok in your application though.

Call and ask for 6061 grade T6 aluminum. Its the same stuff most chassis and hop up parts are made of.

Another good way to get metal is www.Onlinemetals.com