Another reason mandrel expanders are the way to go. Loading two batches of 223 AI for two rifles using bushings. Standard necks as well as turned necks for a custom .242 chamber.
The standard necks thickened from .247 on 1F to .254 on 3F. Loaded additional 1F rounds to verify measurements. Runout was surprisingly good at 0.002.
No change in 3F neck turned brass, likely because of the cut into the shoulder to prevent doughnut formation. .241 stayed at .241. Runout was 0.001
Neither grew, sitting at 1.750 for all three firings.
I might have to start lightly turning the brass for my standard chamber, and my bushings are now the wrong size. Or give up and use an expander mandrel.
The standard necks thickened from .247 on 1F to .254 on 3F. Loaded additional 1F rounds to verify measurements. Runout was surprisingly good at 0.002.
No change in 3F neck turned brass, likely because of the cut into the shoulder to prevent doughnut formation. .241 stayed at .241. Runout was 0.001
Neither grew, sitting at 1.750 for all three firings.
I might have to start lightly turning the brass for my standard chamber, and my bushings are now the wrong size. Or give up and use an expander mandrel.