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What you're really getting at when you ask about the busing vs bull barrel setups is the method of dis-assembly and the convenience (or inconvenience) of each method. All 1911s can be made to shoot extremely accurately whether they're bushings or bull-barrels. Not all 1911s come from the factory that accurate though.
The bushing setups can be dis-assembled with your fingers (if they're a true GI setup) or with strong fingers, any hard object, or the little tool that comes with most 1911s. Once the recoil spring is out, the rest is very similar to a bull-barrel takedown.
The bull-barrel setups use a pin that looks like a thin but long allen-key with no sides to it. (or like a long L shaped paperclip) This tool is inserted into a small hole drilled in the guide rod when the slide is fully locked back. Then you can release the slide onto this little pin and it will hold the recoil spring coiled tightly on the guide rod assembly so you can then move the slide to the dis-assembly notch and the take-down is the same as any government model is from there.
Which method do you prefer?
The accuracy is good either way.
I've got hundreds of thousands (no joke) rounds through a few 1911A1's (I was lucky when I was in the service). Some were much more accurate than others. This had more to do with parts wear, barrel wear and also a bit of "luck" on the production line. I never got a chance to fire them at 25 yards, just 15 yards max, but accuracy was often ragged-holes from good pistols.
I've fired a Kimber Gold Match II which is a 5" bushing barrel setup. It's very accurate.
I've also fired a Kimber Crimson Carry II which is a 4" bull-barrel setup (with a crimson trace lasergrip). It's very accurate (off of the irons or the laser) and actually slightly more accurate than the Gold Match II is. I'm not sure if it's because of how close the tolerances were held to or if it's just a "10am Tuesday morning" gun.
My H&K USP Tactical is more accurate than either, but it's the equivalent of a hand-fitted bushing setup in that it has an O-ring groove with replaceable O-rings to act like a hand-fitted busing setup.
When I say "very accurate" "more accurate" and "most accurate, I'm splitting hairs since they're all shooting ragged holes under 1 inch. (This is on a good day, from a rest and only when I, the fallible shooter am at my best.)
At 25 yards, the 5" bushing setup is grouping right at 1 inch from a rest. The bull-barrel setup is grouping around 0.90 to 0.95 inches and the USP Tactical O-ring setup is grouping between 0.80 and 0.90 inches.