I don't think the removal of the "gas adjust" knob is something they really expect you to do at all (let alone often), hence it not being covered in the manual. All it does is give you access to the gas port.Thanks so much for the information. I've read and reread manual. I knew all of it wasn't there and I looked all over for it without finding it. Again thanks! Manual doesn't say how often to clean gas assembly but it doesn't sound like something I would want to do every time I shoot.