"It's not a matter of how tight a barrel is in lock up, but how consistent a barrel returns to the same place after cycling. Since the fixed barrel of a blowback pistol never moves it has the greatest chance of being the most accurate. That is why the .22lr semi-auto pistols can be so accurate."
The barrel on my Benelli is fixed, but the slide has both front and rear sights attached to it, and the slide may or may not be in exactly the same relative position for each shot.
With a pistol that has the sights attached to the barrel, as in an artillery Luger (for instance) the sights can't move relative to the axis of the bore while a standard P08 has some movement built into the rear sight (I'm talking just sights and barrel, not trigger or anything else). A Ruger target .22 is a good example as the rear and front sights never move. In practice a Colt target .22 with the rear sight attached to a moving bolt may be more accurate but it would seem (To me at least) to be in spite
of the moving sight.
If it's got a moving slide with sights attached some means would have to be used to ensure that the sights are in the same place relative to the bore, and the 1911 does a great job of that.
I guess what I keep thinking is that just because the barrel doesn't move that's no guarantee that the sights won't move, and the rotating barrel designs I've seen don't make the sight alignment any surer than a well locked up swinging barrel design. But heck, maybe I'm wrong.