Just another note about the barrel/bushing fit

The barrels are turned on a lathe and I believe the bushings are cast, that's why they're brittle. The bushings are fit to the barrel on a spindle hone similar to honing a brake cylinder. There is no advantage to tightening the bushing into the slide, just snug at the closest notch in the bushing. It's all in the diameters of the barrel compared to the bushing. Each individually done by hand and left to the fitters "feel".