I agree with about everything you are saying except you leave out the most important variable, the bullet quality. And knowledge gained before true premium bullets came out adds little to the knowledge base on the positive side.
And monmetals is where I think premium bullets start.
You are correct that bullet construction makes a big difference. I know some and probably most of the .243 failures I've see were with cup-and-core bullets used by both adults and younger hunters. It wouldn't surprise me if every case was one where the cheapest Winchester or Remington ammo on the shelf was the one used.
As to premium bullets, I fully admit to being biased in their favor. If I was shooting a .243 it would be with TTSX bullets. We do disagree somewhat on where Premiums start. I run Barnes MRX (what few I have left) and TTSX, Swift A-Frame (.257 Roberts only), North Fork SS and FP, Nosler AccuBond and Swift Scirocco II (6.5-06AI only). The only cup-and -core bullets I use are in low muzzle velocity applications -- my handguns, lever guns and Nosler BT in my 16.1" barreled .308 Win Ruger Scout.
