I have the same barrel. I was a bit perplexed by the lack of flash hiders in this thread pitch. You'll have to look for a .458 SOCOM flash hider if you want to find anything in this thread pitch.
I used a Wilson Combat .458 accu-tac flash hider on my Franklin Armory .450 BM barrel with no issues (different thread pitch, but same idea/application).
Here's one - scroll to the bottom of the page.http://www.sbrammunition.com/458socom_parts.html
Here's another, looks pretty much like the one above:http://www.dark-storm.com/dsi-phantom-f ... socom.html
For what it's worth, I ended up ordering a Ross Brake. For $35 you can't go wrong.
Never give the devil a ride, 'cuz pretty soon he'll want to drive.