sub-moa
US Veteran
So, my understanding is that you use the term "fixed barrel bushing" meaning "bushingless" design?
WADR, I'm not clear as to how one would arrive at that "understanding", but it would be an incorrect "understanding". I simply pointed out that FN toyed with the 1911 removable barrel bushing design in late '20s prototypes...discovered that design offered no advantage, and reverted to their original "Fixed Barrel Bushing" design for production P35 pistols. A "Fixed Barrel Bushing" design is not a "bushingless" design.
There's a whole involved history of JMBs evolving locking systems...and the muzzle support designs that evolved to support them. Suffice it to say that each design had both strong and less strong

Even the "bushingless" design, which evolved from the original 1911 removable bushing design, uses the inside diameter of the slide mating with the larger diameter coned barrel to form a bushing interface.