I like to pay a lot of attention to the gas tube alignment. There is a little gas tube/gas key click in my current build. Nothing major, the gun passes the 45 degree test without a noticeable resistance when the carrier (without the bolt) slides down. It even passes an 30 degree test. It's just that little click which is bugging me a bit. When I slide the carrier home by hand I can feel the click a tiny little bit but no restance. I also made sure that the delta ring, weld spring and the snap ring don't touch the gas tube. What are your thoughts on this? Is it even possible to align it perfectly? I mean even if you get it to align so that you can't even hear an click, since the carrier has some play in the upper receiver and might behave differently under live fire so that it hits the gas tube slightly different that at home on the bench.