Slide to frame fit and accuracy

Which one improves accuracy the most : fitting match barrel and bushing? Or tightning frame and slide fit ?

Barrel fit. It will remove majority of vertical play and some horizontal. Frame to slide is very small percentage of accuracy. In my opinion less than 10%, much less.
Jon

Jon would know. He built my gun and guns for many other shooters. Tack drivers all of em.

loose guns can still shoot well. poorly fit barrel or bushing and it will group like crap. Sprung barrel vertically string.

Barrel to slide, especially if you have slide mounted optics, which virtually everyone has these days. If you have a frame mounted optic, well then slide to frame is pretty important too.

In most cases you will need EVERYTHING right to see any inprovement in accuracy. I have done a lot of 1911 accuracy work and I feel guilty taking a person’s money for “just a bushing”. It all works together as 1 piece. I have seen some guns shoot with a loose slide to frame fit, but normally those guns have a steel compensator to pull the barrel to the same spot in battery. Bullseye guns tend to be more sensitive to slide to frame fit.