I haven't done it, but I am curious why you want to?
Is there something significant to be gained?
I ask because it is not a simple task. You'll need a good armorer's wrench and torque wrench to remove/reinstall the barrel nut, and an upper receiver vise block to hold the receiver while torquing. Of course that's after using a good hammer/punch set to remove the front sight base and gas tube.
None of that is difficult, but to me it does seem like a lot to go through for very little gain, which is why I asked.
Good luck.