RE: Expanding the "new brass" thead
Although I'd prefer not to I have made up brass for my .260 Remington using .243. In order to get the correct headspace and provide for excellent fireforming loads I use this process. Run the new.243 brass thru a 7-08 size die justo get the neck expanded, run that brass into my .260 size die to get that small false shoulder, slight crush fit in my guns chamber. Load at a known near max level and go hunting. These have proven as accurate as standard fired brass handloads.