I agree with Kassie, try lots of other riding ideas..New things to make him think.
Another idea, instead of taking Outlaw to the shows and running him. Take him and make him walk all of the patterns, do not let him have any speed...Now that he's used to showing and has gotten comfortable with you at a show he sees it all as "I have to run in the arena" and will slowly work him into a mess...I'm guessing barrels is at the end of the show? And he's okay and the beginning of the day and then it just gets worse throughout the day? That's because he's having to go in the arena and run many times..He's starting to sour on it and work himself into a mess...Take your home work back to basics and no barrels, take him to shows and make him stay nice, slow, and collected doing all of your patterns..Doing this for a while instead of just run, run, run at every show will take him back to that cool and collected step..it might take a few shows so don't expect this to be fixed in one of two shows..