Bushes and Bushes
Howdy Gary,
I've seen some that were fitted with as little as a half thousandth clearance,
but match specs usually stay to about .001 inch or so. As long as the barrel will fall into the slide without springing, and will fall into bed without having to be pushed, it'll work. The tightly fit bushings need to be clearanced in key areas, which may also include turning the barrel OD on a lathe with a turning fixture and a live center.
As to whether it'll tighten your groups to any apreciable degree...it depends.
Accuracy...or the lack thereof...depends on several things. The bushing is just one. How well does the barrel hood fit into the slide? How much fore and aft play does the barrel have when it's in the slide with the bushing in place? Does the barrel lock vertically on the lower lug and slidestop pin...or does it stand on the link? How is the headspace?
MGW markets a very good "Drop-In" fit bushing that is cut to the high side of
tolerance on the OD...or about .700 inch...and averages about .583 on the ID.
Those specs alone will reduce slop at the front quite a bit, and most don't require more than a light, final lapping in the slide. That'll help a little...but how much improvement depends on how the rest of the key areas stack up.
Remember...There's no guarantee of a drop in fit, no matter what the package says. Check to see that the barrel engages the slide without springback, and that it falls to bed freely.
Hope this helps...
Tuner
