A 1911 with proper lockup should be tighter than a rotating barrel gun. When the barrel is locked up there can't be any movement at all, the front of the barrel is tight at the top of the (closely fitted) bushing and the locking lugs are bound to the slide lugs, the bottom lugs are tight to the slidestop pin.
Granted, few 1911's are that tight, but when they are the barrel is very rigid, repeatably, while the rotating barrel has to have at least some rotational clearance. Just being the odd guy out here.
I think it's a straw dog argument that a "fixed" barrel like a Ruger target .22 (front and rear sights fixed relative to barrel at all times) has to be more accurate. More likely to? Yes, nothing to loosen up.
I have CNC produced 416 stainless triggers to replace the plastic triggers on Colt Mustangs, Mustang Plus II's, MK IV Government .380's and Sig P-238's. Video on installation in Sig;http://www.youtube.com/watch?v=Jh2v_-87DRM