Does anyone else understand what I am trying to say? Let me try again.
When I look at your installed extension. starting from the rear barrel lug, I see a gap showing the factory mag tube, then the start of the extension large OD. It then steps down to a smaller OD to the front barrel lug.
What I want to see is no gap at the rear barrel lug, the factory mag tube is covered. The extension will fill the full visible distance between the two barrel lugs and be the same outside diameter tube starting at the rear barrel lug all the way up to the front barrel lug, no step down on visible on the outside. The inside is still blocked at legal capacity but looks like a straight tube from outside.