DF,
I bet it shows some throat erosion in 200 rounds. That's because I've seen "some" throat erosion in 200 rounds in a 7mm STW, and even in a .223 Remington.
Throat erosion is an inevitable fact with most modern centerfire rifle cartridges. I can even see a trace in my Ruger No. 1B .22 Hornet, though it's more a slight rounding of the lands in the throat, rather than any cracking.
The real question is how long a barrel will shoot accurately enough for what's desired by the shooter. I doubt any competitive shooters will be using the 26 Nosler. Instead they'll be hunters, some of whom may be totally satisfied with the accuracy after 1000 rounds, or even more.
And some people may not want to run it full-out. One of the more interesting aspects to me is that it will probably get 3200 fps out of 140'sat less-than-max pressures. That's been the Holy Grail with .264 fans for many years, and they've gone to a lot of trouble to get there. Usually when it happens, it's in a 26" barrel and with one or two rather specialized powders. My guess is the 26 will do it easily in a 24" barrel with several powders.
We'll see.
