Sorry , I might shoulda ' 'splained that I was addressing the second sentence in your post .The three cartridges I mentioned are the same case with three different bore sizes .
Your statement is true when dropping from .284 to .277 . Not true from .277 down to .257 . At least in my rifles .
And , the 300 and 338 ultras like the same powder . Granted , those cases ain't exactly the same .
This just proves that when anybody posts a " truism " , some bonehead will try and point out an exception .
