OK, did you try adjusting the screw again? Don't hold back on the trigger when this happens or you'll cook your motor for sure. If adjusting the screw dosen't do anything, take the end cap off and pull the motor out and check the condition of the gear, clean it up if necessary and reinstall it. Try it again but remember to only pull back on the trigger breifly or you'll cook the motor with that big battery.
I guarantee my work Nate so if there's a problem just get the gun back to me and I'll take care of it.