In comparing the "Before" and "After" chamber dimensions, I'm just curious how reaming out the chamber to .450 BPE could accomplish REDUCING the diameter of the chamber at the case mouth from .490" to .479", REDUCING the chamber diameter in front of the rim from .550" to .545", and also REDUCING the rim thickness from .060" to .040"

A reamer that deposits metal in addition to removing it is indeed a remarkable thing!

A true sign of mental illness is any gun owner who would vote for an Anti-Gunner like Joe Biden.