No need to remove anything other than the roll pin that secures the gas tube and the gas tube itself.
^This-soak the gas block/tube junction with some bore cleaner or Kroil and let it set a while. When you get the pin out gently rotate/wiggle the tube out of the block. Push the tube into the upper a bit until it clears the block and retaining ring and remove.
The most important thing to be learned from those who demand "Equality For All" is that all are not equal...
Gun Control - seeking a Hardware solution for a Software problem...