Briley Spherical Bushing Mandrel 1911 Government
Briley has listed installation instructions for the bushings:
The spherical bushing is designed to increase accuracy and reliability by maintaining perfect alignment from barrel to slide by a unique system using a spherical ring. If the spherical bushing is disassembled, re-insert the ring in the horizontal cut and rotate to seat. Ensure that there is linear movement in the assembly. Lateral (axial) movement should be non-existent and is best checked in your gun when in the locked position to avoid misinterpreting axial movement with pivot.
Ring to Barrel Fit: Simply measure barrel at the muzzle and ensure that the number on the ring is .001 of an inch larger than the outside diameter (i.e. a .582 barrel O.D. should be fitted to a .583 ring). For those using an undersized ring (.575) a competent gunsmith should exercise care in not turning the barrel more than .001 under the size of the ring.