I see a lot of posts with people bragging about their slide to frame fit being tight on their Les Baer etc. Does slide to frame fit contribute that much to accuracy or is it mostly barrel to slide/barrel to bushing fit? Thanks.

my baers have a good slide to frame fit , its the lock up that makes it tight. the bbl fits tight in the slide and bushing making it feel like the slide is tight or at least thats how mine are.

From the 10-8 Performance site-

Slide/frame fit:

This only contributes about 5% to accuracy, but it changes the feel and longevity of the gun. The slide/frame fit gives the final 15-20% of the smoothness to a gun fit with a match barrel. A properly fit gun will shoot very smoothly, and does not have the sloppy feel in recoil of guns that rattle from an excessively loose slide to frame fit. Some play between the slide and frame is not the end of the world, and can be helpful in a gun that will be around a lot of grit and dirt. A duty grade gun does fine with a smooth, but only moderately tight slide to frame fit.

LINK

I have an older SA Gi repro that I modded/tuned up and the frame/slide is still loose, even after tightening.  It rattles when you shoot it and you can feel the play in the slide/frame fit.  Stupidly accurate though!  My DW VBOB and Les Baer Custom Carry and my moms CBOB and Les Baer Commanche, have much nicer fit slides and there is a noticeable difference in shooting the looser pistol vs the tighter ones.

In the late 70's all the 1911A1's we had in our company armory where WW2 guns.  Remington Rand, Ithaca, US&S, Singers, etc.  If you gripped them firmly and shook on it rattled like a can of nuts/bolts.

Everyone I fired would consistently hit man sized targets at 50 meters with GI ball ammo.  After that, I never worried about frame to slide tightness, or lack of it.  

Some people look/think of it as sloppy manufacturing but I think of it as - it'll work longer dirty/cruddy/wet in the field.

And let's not forget about pride in ownership

Barrel bushing fit is way more important than slide to frame fit. Think about it, the sights are on the slide, the barrel is mostly positioned by the slide.

Having a tight slide to frame fit is more important for the safe guns. If you run it in varied temperatures, dusty areas or really hard until it is hot you want some clearance.

It really don't matter unless you have a Colt that's so fukkin' loose it ain't worth fitting a new barrel to without welding the rails up and re-fitting.

All the high end builders fit 'em about the same, the barrel lock up is what makes the gun seem tight.  But most of the folks who worry about slide to frame fit are the ones who worry about holster wear and give 'range reports' showing a shotgun pattern at 15'.

Lock-up shot to shot is more important then slide fit.  I've had more than one 1911 'smith tell me that.

The fit on my Commander is a couple steps from a GI sloppy slide but nowhere near high-end super tight.