The 280 grain Barnes isn't too much for blacktail, infact i am using that combo for antelope, deer, and elk this year.
The Smk has been proven time and time again on game at long range but I am not sure about close range/ high velocity impacts as I have never used them.
Now to the Berger
, i am not a fan of Berger bullets, I have never used them, but I don't like the way they are supposed to do their damage on game. Just me. Broz on here uses the Berger with success, you might want to send him a pm if he doesn't jump in on this conversation.
At the relativly low velocities the 338 Lapua works at with 280-300 grain bullets you shouldn't ruin very much meat. You will probably have more meat damage with lighter/faster bullets in the 200-225 grain range.
I hope this helps with your decision.
BTW the 225 grain Nosler accubond has been used a LOT by LR hunters. Do a search in the upper right corner.