Re: Best New cartridge in 20 years. I might answer 6.5x47 Lapua.
Granted you don't find many factory rifles and affordable ammo.
Jeff - you said "HBR" - guessing you have an MBA? DC223 - 130 NABs work well. Not that others might not have an edge.
GA Boy - indeed. Folks finally thinking as I did 20+ years ago. 6.5's. Smaller rounds that beat your shoulder and ears up far less.
Take a look at the 47, and if you want to take it a step further - a 6.5BR or Grendel.
Yes to the MBA, Class of 1986. I was the oldest guy in my class at 31, the only veteran, and filling a minority slot for the first time in my life as the class was demographically divided at about 30% Chinese, 30% Indian, 30% Jewish, and 10% Other.