I have a muzzle brake I accidentally bought that has 9/16"-28 TPI and I have a barrel I could thread to that size but for the life of me I can't find a die in that size. Anybody have any ideas to help me find one????

look here

die

Those threads will have to be cut on a lathe. You can't cut them with a Die. The barrel is not soft mild steel.

http://www.brownells.com
They have the die.
If you have a lathe you can chuck the barrel in the headstock along with a steady rest about half way down the barrel and center the die on the tailstock.
Bring the tailstock to bear on the muzzle then back it off and install the die and reset the tailstock.
Hand turn the headstock until the die begins to cut, then set your speed and turn on the lathe and feed the die onto the barrel.

Don't have a lathe?
You can install the barrel between a long clamp using a bore mandrel.
Use the clamp to center the die against the muzzle, then hand turn using a die wrench.

The advantage of a die over a lathe cut thread is that you will obtain much cleaner and more uniform threads using a die.

Thanks for the help guys! I will check out both of the links right now. Oh and I threaded a barrel using the setup in blue last year, it took a lot of patience but it worked perfect!!! The key for me is that that barrel and the current barrel diameters were already very close to the diameter of the muzzle brake (very thin barrels). The first barrel was for my mini-14. Here is a pic of that one with the muzzle brake on.